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1
Mrózek, Jan. "NVH analýza pohonné jednotky." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2021. http://www.nusl.cz/ntk/nusl-444965.
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This master thesis is focused on the diagnostics of vibrations and noise of an internal combustion engine. The work also includes a summary of the current state of knowledge in which the quantities used, transmission paths, measuring devices and the possibilities of performing frequency analysis are analysed. As part of the technical experiment on which this work is based, vibrations and noise on the tractor engine are measured. The obtained data are then further processed using the BK Connect program. Subsequently, a frequency analysis is performed, specifically an order analysis. The conclusion of the analysis consists of an evaluation of individual orders that cause excitation that occur in the investigated motor.
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David, Jan. "NVH převodového ústrojí pro elektromobily." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2020. http://www.nusl.cz/ntk/nusl-433548.
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This master’s thesis deals with determination of NVH parameters of the gearbox housing for electric vehicle. The introduction part is focused on the theoretical knowledge of this issue. Subsequently, the deviations of geometry on the gearbox were measure by 3D scan method. The next part of thesis is focused on the modal analysis, which is solved by numerical approach and followed by experimental verification. During the numerical calculation solving, the influence of the screw preloading on the modal properties of the structure, was also taken into account. Numerical harmonic analysis was then performed and the results were compared with the experimental approach. The conclusion is devoted to material damping and comparison of the individual results.
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Belák, Kristián. "Určení NVH parametrů skříně převodovky." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2018. http://www.nusl.cz/ntk/nusl-378021.
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This master’s thesis deals with determination of NVH parameters of the gearbox housing. Introductory part is focused on the necessary theoretical knowledge. Subsequently, it contains the modal analysis with the computational and experimental approach, which are being compared to each other. In the case of the computational approach, analysis of the influence of bolt pretension on the modal properties is also involved. The thesis continues with the harmonic analysis with the computational and experimental approach, including their mutual comparison. Based on these analyses, design modifications for improvement of the NVH parameters are designed at the end of the thesis, which are being compared to each other and to the original geometry, using the computational approach.
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Bouchner, Michal. "Určení NVH parametrů rovinné desky." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2018. http://www.nusl.cz/ntk/nusl-378142.
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The aim of this thesis is examination and verification of numeric model for solving acoustics and vibration problems. Specifically, we are speaking about cast iron plate machined from gearbox. Main objectives of this work is set of experimental and numerical analysis at this simplified part with follow-up numerical model, where same analyses examining not only structure, but especially acoustic space around were performed. Due to this we were able to compare data between experimental and numerical analyses and to be able to prove or disprove functionality and limitation of numerical model.
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Drtílek, Juraj. "Experimentální identifikace NVH brzdových soustav." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2017. http://www.nusl.cz/ntk/nusl-318537.
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This Diploma Thesis is dedicated to solve the source of noise, observed during braking processes on tested vehicle, called Gouki noise and has been worked out in corporation with Federal Mogul company. The aim of this work to create test methology, which allows to experimentally detect the source of undesirable noise and eventually suggest next steps in its prevention.
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Von, Gossler Joring. "NVH benchmarking during vehicle development using sound quality metrics /." Link to the online version, 2007. http://hdl.handle.net/10019/486.
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Jaber, Mariam [Verfasser]. "Optimization of NVH Performance in Vehicle Structures / Mariam Jaber." München : Verlag Dr. Hut, 2019. http://d-nb.info/1181515440/34.
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Von, Gossler J. "NVH benchmarking during vehicle development using sound quality metrics." Thesis, Stellenbosch : University of Stellenbosch, 2007. http://hdl.handle.net/10019.1/2955.
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Thesis (MScEng (Mechanical and Mechatronic Engineering))--University of Stellenbosch, 2007.<br>Noise, Vibrations and Harshness (NVH) characteristics are becoming ever more significant in
today’s vehicle manufacturing industry. Similar to good vibration and harshness characteristics,
the perception of a vehicle’s quality is enhanced by a well sounding vehicle interior.
This study’s main aim was to develop objective equations to directly optimise interior sound
quality of light commercial vehicles ( ½ ton LCVs) on the South African market. The effects the
noise of the engine, the wind and road/tyre interaction during steady-state conditions have on
the interior sound quality of eleven comparable vehicles was investigated with the aid of a
binaural head. Steady-state condition in this content refers to the fact that vehicles were tested at
constant speeds, no acceleration involved. A strong emphasis was laid on the influence road
noise has on the interior sound quality of LCVs.
Other objectives for the thesis were, to provide a method to benchmark the interior SQ of LCVs
and to develop target values for objective metrics for these vehicles. Establishing a
comprehensive literature survey formed another objective of this study. It seeks to provide a
summary of the modern SQ analysis procedure and the findings of a number of studies. The
survey also presents an opportunity to compare this thesis’s results with previous studies. A last
objective was to develop a list of possible hardware modifications that would improve the
vehicle interior sound quality, influenced by different noise sources.
A strong correlation between vehicle and engine speed and Zwicker loudness as well as Aure
sharpness was found, for all test conditions. The road surface roughness was observed to also
have a strong influence on the objective metrics of vehicle interior SQ. Loudness was found to
be around 25% higher and sharpness around 5.6% lower in vehicles driving on rough tar roads
than on smooth roads.
Good correlations between a newly developed metric (the SPF), an equation in Zwicker
loudness and Aure sharpness, and subjective ratings was obtained for a number of test
conditions. Four objective equations, as well as target values for loudness and sharpness have
been developed to objectively optimise the sound quality of LCVs. Benchmarking interior
sound quality utilising the developed equations, will ensure continuous improvements in the SQ
sector for future LCVs.
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Cantalogo, Alexsander. "Modelagem de \'Deadeners\' usando NASTRAN e correlação experimental." Universidade de São Paulo, 2012. http://www.teses.usp.br/teses/disponiveis/18/18149/tde-13032012-085537/.
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Este trabalho visa o desenvolvimento de um modelo em elementos finitos de elementos de dissipação vibratória de base betuminosa, chamados comumente de deadeners. O modelo baseia-se no algoritmo comercial MSC/NASTRAN e é correlacionado e verificado com base em dados experimentais de laboratório. O resultado final deste projeto é um modelo para os deadeners que pode ser utilizado em modelos de elementos finitos de veículos completos, facilitando assim a definição da melhor localização dos mesmos no veículo bem como a otimização de seu uso. O modelo tem melhor resultado em termos de amplitude para frequências abaixo de 200Hz, porém apresenta tendências de superestimar o efeito do amortecimento nos picos de ressonância<br>This project aims the development of a finite element model of vibration dissipating elements of bituminous base, commonly called \"deadeners. The proposed model is based on the finite element commercial algorithm MSC/NASTRAN and is correlated and verified on experimental data from laboratory. The end result of this project is a model for \"deadeners\" which can be used in finite element models of complete vehicles, thus facilitating better definition of their location in the vehicle as well as the optimization of its use. The model has a better result in terms of amplitude for frequencies below 200 Hz, but shows a tendency to overestimate the effects of damping at the resonance peaks
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Sacka, Michelle Lorraine. "A system engineering approach to improving vehicle NVH attribute management." Thesis, Massachusetts Institute of Technology, 2008. http://hdl.handle.net/1721.1/43111.
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Thesis (S.M.)--Massachusetts Institute of Technology, System Design and Management Program, 2008.<br>Includes bibliographical references (p. 134-137).<br>This research is comprised of a detailed study of attribute management processes at a North American Automotive OEM (NA OEM) that has just introduced a new product development system intended to drastically reduce product cycle time and expedite product time to market. In specifics, the product development processes and organization that manage the delivery of a vehicle system design that meets or exceeds customer expectations for noise, vibration and harshness (NVH) are studied. Systems engineering principles, methods and tools are applied to the current processes to assess if process lead time, resources and product quality improvement can be realized. The systems engineering Design Structure Matrix (DSM) method for product development process modeling is applied to the current process used to manage the highly cross functional vehicle attribute known as second order NVH. Second Order NVH represents a vehicle system attribute that is owned by a single subsystem, yet controlled by design parameters owned by many other subsystems. The DSM method enables the NA OEM PD organization to understand the current process of managing this highly cross functional attribute and serves as a powerful tool for process restructuring. Process data is collected such that the DSM process model can be input into a simulation program which predicts stochastic process lead time for the current process and tests the impact of process restructuring ideas. This research also studies the methods and tools used at NA OEM to facilitate vehicle attribute trade-off, decomposition and cascade to the subsystem and component level. Then, a systems engineering approach is suggested to improve the attribute engineering knowledge base which could enable improved attribute trade-off, decomposition and cascade.<br>by Michelle Lorraine Sacka.<br>S.M.
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COLANGELI, CLAUDIO. "Clustering Inverse Beamforming and multi-domain acoustic imaging approaches for vehicles NVH." Doctoral thesis, Università Politecnica delle Marche, 2017. http://hdl.handle.net/11566/245537.
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Il rumore percepito all’interno della cabina di un veicolo è un aspetto molto rilevante nella valutazione della sua qualità complessiva. Metodi sperimentali di acoustic imaging, quali beamforming e olografia acustica, sono usati per identificare le principali sorgenti che contribuiscono alla rumorosità percepita all’interno del veicolo. L’obiettivo della tesi proposta è di fornire strumenti per effettuare dettagliate analisi quantitative tramite tali tecniche, ad oggi relegate alle fasi di studio preliminare, proponendo un approccio modulare che si avvale di analisi dei fenomeni vibro-acustici nel dominio della frequenza, del tempo e dell’angolo di rotazione degli elementi rotanti tipicamente presenti in un veicolo. Ciò permette di ridurre tempi e costi della progettazione, garantendo, al contempo, una maggiore qualità del pacchetto vibro-acustico. L’innovativo paradigma proposto prevede l’uso combinato di algoritmi di pre- e post- processing con tecniche inverse di acoustic imaging per lo studio di rilevanti problematiche quali l’identificazione di sorgenti sonore esterne o interne all’abitacolo e del rumore prodotto da dispositivi rotanti. Principale elemento innovativo della tesi è la tecnica denominata Clustering Inverse Beamforming. Essa si basa su un approccio statistico che permette di incrementare l’accuratezza (range dinamico, localizzazione e quantificazione) di una immagine acustica tramite la combinazione di soluzioni, del medesimo problema inverso, ottenute considerando diversi sotto-campioni dell’informazione sperimentale disponibile, variando, in questo modo, in maniera casuale la sua formulazione matematica. Tale procedimento garantisce la ricostruzione nel dominio della frequenza e del tempo delle sorgenti sonore identificate. Un metodo innovativo è stato inoltre proposto per la ricostruzione, ove necessario, di sorgenti sonore nel dominio dell’angolo. I metodi proposti sono stati supportati da argomentazioni teoriche e validazioni sperimentali su scala accademica e industriale.<br>The interior sound perceived in vehicle cabins is a very important attribute for the user. Experimental acoustic imaging methods such as beamforming and Near-field Acoustic Holography are used in vehicles noise and vibration studies because they are capable of identifying the noise sources contributing to the overall noise perceived inside the cabin. However these techniques are often relegated to the troubleshooting phase, thus requiring additional experiments for more detailed NVH analyses. It is therefore desirable that such methods evolve towards more refined solutions capable of providing a larger and more detailed information. This thesis proposes a modular and multi-domain approach involving direct and inverse acoustic imaging techniques for providing quantitative and accurate results in frequency, time and angle domain, thus targeting three relevant types of problems in vehicles NVH: identification of exterior sources affecting interior noise, interior noise source identification, analysis of noise sources produced by rotating machines. The core finding of this thesis is represented by a novel inverse acoustic imaging method named Clustering Inverse Beamforming (CIB). The method grounds on a statistical processing based on an Equivalent Source Method formulation. In this way, an accurate localization, a reliable ranking of the identified sources in frequency domain and their separation into uncorrelated phenomena is obtained. CIB is also exploited in this work for allowing the reconstruction of the time evolution of the sources sought. Finally a methodology for decomposing the acoustic image of the sound field generated by a rotating machine as a function of the angular evolution of the machine shaft is proposed. This set of findings aims at contributing to the advent of a new paradigm of acoustic imaging applications in vehicles NVH, supporting all the stages of the vehicle design with time-saving and cost-efficient experimental techniques. The proposed innovative approaches are validated on several simulated and real experiments.
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Allemang, Matthew R. "Comparison of Automotive Structures Using Transmissibility Functions and Principal Component Analysis." University of Cincinnati / OhioLINK, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1367944783.
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Yuan, QingHui, and Aaron Jogada. "Architecture, Control and NVH Development of Digital Hydraulics for Off-Highway Vehicle Applications." Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2016. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-199396.
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Digital hydraulics is one of promising technologies having a huge potential to significantly improve energy efficiency in the fluid power industry. In this paper, we present a digital hydraulics solution for mobile market with a large ammount of energy usage by hydraulic components and systems. Specifically, a novel hydraulic architecture, Multiplex Digital Valve (MDV) system that employs digital valves to meet multiple service pressure/flow requirement in off highway vehicles, is introduced. With MDV being integrated in an execavator, signficant hydraulic power saving have been validated compared to the baseline machine with the negative flow control (NFC) architecture. In addition, considering noise is still a critical hurdle for digital hydraulics to be adoped, we develop several noise reduction methods that have been evaluated in simulation environment and implemented in the above MDV. The sound pressure measured from the retrofitted MDV solution with the NVH treatment in the excavator has been improved signficantly over the untreated system such that it is nearly comparable to the baseline machine. The paper also briefly presents the sound quality study for better understanding of human perception and acceptance to nonconventional sound.
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Parkkila, Teija, and Johan Jonson. "Stomljudsisolering : jämförelse av processmöjligheter." Thesis, University West, Department of Technology, 2003. http://urn.kb.se/resolve?urn=urn:nbn:se:hv:diva-765.
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Kihlander, Jesper. "Finite Element simulation of vibrating plastic components." Thesis, Linköpings universitet, Hållfasthetslära, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-89984.
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For automotive plastic parts there is a clear demand on an increased quality of the FE models. This demand is related to the increased use of simulations, both due to a reduced number of prototypes and an increased number of load cases. There have been studies showing a change of dynamic properties in injection molded components. The conclusion from these studies are that the change depends on residual stresses built in during the injection process. This study use simple models to try to get a working method and from the results find out the basic relations between residual stresses and dynamic properties. A method was developed and the results showed that the residuals had a major impact on the dynamic properties. Continuation on this work would be to use more complex models, to try to mimic results from reference studies and tests.
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Simões, Pedro César Dinis. "Análise da correlação entre resultados experimentais e numéricos de NVH em bombas de óleo." Master's thesis, Universidade de Aveiro, 2017. http://hdl.handle.net/10773/21168.
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Mestrado em Engenharia Mecânica<br>O presente trabalho aborda o problema do NVH (Noise Vibration and Harshness) em bombas de óleo. Neste âmbito, é realizada numa fase inicial uma descrição das bombas de óleo quanto à sua constituição e princípio de funcionamento, sendo que a bomba utilizada neste trabalho é uma bomba de palhetas de cilindrada variável. A utilização destas bombas acarreta a vantagem de permitir uma melhor eficiência do motor do veículo, logo a tendência para as utilizar e estudar é cada vez maior. Assim, estre trabalho teve como objetivo perceber a correlação existente entre os dados numéricos e experimentais de NVH provocado por uma bomba de cilindrada variável. A componente de NVH estudada foi o ruído com origem no fluido (fluidborne noise), que neste caso é o óleo. Relativamente às bombas de óleo este tipo de ruído é provocado pela pulsação da pressão na zona de descarga. Ao sinal desta pulsação, que tem como unidades o bar em função do tempo, foram aplicadas as transformadas de Fourier para passar para o domínio da frequência e uma fórmula para converter o sinal para a escala de decibel. O software utilizado para o efeito foi o LMS Test.Lab da Siemens. Os dados de simulação obtiveram-se a partir de um modelo previamente criado no seio da empresa com o software GT-Suite. Os dados experimentais foram obtidos pela utilização de um banco de ensaios presente na Renault – Cacia, o banco RO6. Comparam-se os valores da frequência dos harmónicos teóricos e numéricos, concluindo-se que existe uma boa correlação entre estes. Verificou-se igualmente que o valor na frequência dos harmónicos do sinal experimental é coincidente com os dois anteriores. Pode-se afirmar que nesta parte o modelo numérico traduz bastante bem aquilo que ocorre na realidade e, portanto, é válido relativamente ao valor da frequência nos harmónicos. Complementarmente analisou-se o sinal numérico ao longo da velocidade de rotação da bomba e ao longo do espectro da frequência onde se compararam sinais com diferentes temperaturas (20°C e 80°C) e modos de configuração da electroválvula (ON e OFF). É possível concluir que segundo o modelo numérico o ruído nos harmónicos tem um comportamento crescente e linear até cerca das 2200 rpm, depois desta velocidade torna-se difícil de arranjar um padrão para o seu comportamento na medida em que este depende mais das condições de temperatura do óleo e estado da electroválvula da bomba. Das comparações entre os dados numéricos e experimentais verificou-se que ocorre uma correspondência razoável, com valores de correlação entre 0.69 e 0.85 de correlação. Verificou-se ainda que o valor dos harmónicos numéricos é quase sempre superior aos experimentais e que os resultados foram melhores quando a electroválvula se encontra no modo de configuração ON do que em OFF.<br>The present work approaches the problem of NVH (Noise Vibration and Harshness) in oil pumps. In this context, it was made, in an initial phase, a characterization of the constitution and working principle of some oil pumps, like the variable displacement oil pump used in this work. This type of pumps has the advantage of improving the engine’s efficiency, thus the tendency to apply and study them is increasing. So, this work had as its main objective to analyse the correlation between the numerical and experimental data of NVH produced by a variable displacement oil pump. The NVH component studied was the fluidborne noise, that is, the noise that has its origin in the fluid, that in this case is the oil. In an oil pump this type of noise is caused by the pressure pulsation at the discharge zone. The Fourier transform is applied to the signal that contains this pressure pulsation, which afterwards is converted to the decibel scale. The software used to make this procedure was LMS Test.Lab created by Siemens. The simulation data were obtained from a model previously created by the company using the software GT-Suite. The experimental data were obtained using a test bench from Renault – Cacia, the RO6 bench. The frequency values of the theoretical and numerical harmonics were compared and it was concluded that they have a good correlation. It was also found that the value of the frequency of the experimental signal coincides with the two previous ones. Therefore, it can be affirmed that in this part the numerical model translates well what occurs in reality, thus it is valid relatively to the frequency value of the harmonics. In addition, it was analysed the numerical signal throughout the pump speed and the frequency spectrum where were compared different signals with different temperatures of the oil (20°C e 80°C) and modes of the configuration of the electrovalve (ON and OFF). It was possible to conclude that, according to the numerical model, the noise in the harmonics has a growing and linear behaviour until about the 2200 rpm. After this speed it becomes difficult to find a pattern because the noise depends more of the temperature of the oil and the mode that the electrovalve is in. From the comparison between the numerical and experimental data it was verified that it occurs a reasonable correspondence, with correlation values between 0.69 and 0.85. It was also found that the value of the harmonics is higher in the numerical data than in experimental data and that the results were better when the electrovalve is ON than when it is OFF.
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Dowsett, Amy. "The improvement of vehicle noise variability through the understanding of phase angle and NVH analysis methods." Thesis, Loughborough University, 2018. https://dspace.lboro.ac.uk/2134/35880.
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Noise, vibration and harshness (NVH)levels in the luxury automotive industry are used by customers as a subjective method of determining the vehicle quality. This can be achieved by adjusting the vehicle design, where simulations are used to predict the NVH behaviour. Changes can be expensive and time consuming when made after the design stage has been completed, so it is important to produce accurate simulations of the product. Variability exists to some extent in all products, even those just off the production line, however, if a high level of variability exists then only a small portion of products will meet the predicted behaviour. The aim of the project is to provide information that may lead to the reduction of variability in an automotive vehicle. This is achieved by quantifying the statistical spread of FRFs (frequency response function) in a set of nominally identical vehicles. Once overall levels have been calculated, the location of the most variable sources can be identified. Project also seeks to develop new methods of analysis for the system phase response to determine whether further information may be extracted compared to the magnitude response. There are three main themes that run throughout this thesis, with the first being the quantification of variability due to the measurement taking process which is covered in chapter 3. A novel application of a method to separate the measurement variability from the overall system uncertainty was achieved as well as the quantification of the vehicle to- vehicle variability. The second theme that runs through the study concerns the identification of variability sources. This is realised in chapter 4 and chapter 6 as a set of structural and acoustic tests on a luxury sedan door. The trim was found to be held to the door panel by a series of 11 polymer clips and 4 metal screws. The variability of small changes to a significant boundary condition at the door trim was quantified, showing that the removal of rigid clips had a more significant effect on the overall variability that if a loose clip has been removed. It was also found that clips at the corners were the most sensitive to change. The final theme outlines and tests new analysis methods on the phase and compares the statistical spread of the phase with the equivalent spread of the magnitude. Data taken from the same tests was used and for most of the cases the two results were found to be approximately the same.
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Renard, Cyril. "Atténuation de structure et bruit de combustion : contribution à l'expertise NVH sur les moteurs Diesel." Le Mans, 2005. http://cyberdoc.univ-lemans.fr/theses/2005/2005LEMA1012.pdf.
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La sévérisation des normes internationales et la demande croissante de qualité et de confort exprimée par la clientèle poussent les constructeurs automobiles à se préoccuper de plus en plus de la mise au point vibroacoustique de leurs Groupes Moto-Propulseurs (GMP). Ce travail de thèse s'inscrit dans le cadre des recherches sur l'optimisation vibroacoustique des GMP et plus particulièrement sur leurs propriétés intrinseques de dissipation de l'energie de l'excitation provenant de la combustion du melange air/carburant : l'attenuation de structure. L'objectif consiste à developper et mettre en oeuvre une nouvelle methodologie de calcul de l'attenuation de structure des moteurs Diesel prenant en compte les contraintes industrielles de temps et de moyens afin qu'elle puisse etre integree dans le processus de conception des GMP. L'enjeu est de taille car il permettra à terme de concevoir des GMP acoustiquement bons dans leurs “genes”. Dans un premier temps, l'etude de la litterature permet dedecrire les mecanismes de transmission de l'energie de combustion. Une première experience basee sur l'analyse de la coherence entre les signaux de pression mesures dans la chambre de combustion et des mesures accelerométriques sur la surface du carter cylindres aboutit à la hiérarchisation des differentes voies de transfert. Les limites de cette approche sont cependant atteintes du fait de la multiplicité des sources en cause et du comportement fortement non-lineaire de la structure dans les cas de forte charge. Les travaux s'orientent alors vers une experience visant à discriminer deux sources preponderantes dans la signature sonore du moteur Diesel : la combustion et le choc de piston. Une identification temporelle et frequentielle des deux sources est alors presentée pour differents points de la surface du carter cylindres. L'extension de cette technique au cas d'autres sources est ensuite abordée. Parallèlement, une modelisation de la principale voie de transmission (voie basse) de la combustion est proposée afin d'etudier le comportement du contact vilebrequin/palier dans les cas de forte charge. Enfin, l'application d'une technique ayant ses origines dans le traitement des images, le filtre de Wiener, permet de determiner les contributions respectives de differentes sources connues a priori. Après une phase de validation du processus d'extraction de sources sur des signaux accelérométriques, la technique est appliquée à des signaux acoustiques. Le bruit de combustion – contribution de la combustion au bruit total rayonné par le GMP- est déterminé et utilisé pour calculer l'attenuation de structure. La methodologie proposée présente un net avantage en termes de mobilisation des moyens d'essais et des prototypes - par rapport à celle jusqu'à présent en vigueur et sous-traitée à des sociétés specialisées. Une comparaison des resultats donnés selon les deux methodes valide la démarche mise en place, et les possibilités offertes par cette technique originale sont évoquées dans le cadre d'une démarche de qualité sonore<br>Nowadays, the rise of international norms and customer's expectations have led on car manufacturers to optimize the vibroacoustic behaviour of their engines. This work focuses on the “structural attenuation” which represents the engines's intern dissipation properties of the combustion excitation. The aim is to develop a new structural attenuation calculation method with regards to industrial constraints. In the first part, the mecanisms of the combustion energy transmission described in the literature are analyzed using the coherence technique leading to the rankness of the different tranfer paths. Nevertheless, the diversity of the excitation sources and the strong non-linearity of the energy tranfer have limited this method. Then the following works tended to identify two main sources responsible for the Diesel engine noise signature in the time and in the frequency domains. Finally, the application of the Wiener filter theory has allowed us to determine the contribution of different known sources. A validation experimentation was performed on the vibration signals measured on the outer surface of the cylinder block in order to extract the contribution of the combustion source. As an application, the combustion noise was extracted from the radiated sound and used to assess the structural attenuation of the engine. The main benefit of this method lays on the experimentation time cost and the possibility of a sound design approach
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Renard, Cyril Pascal Jean-Claude Sahraoui Sohbi. "Atténuation de structure et bruit de combustion contribution à l'expertise NVH sur les moteurs Diesel /." [S.l.] : [s.n.], 2005. http://cyberdoc.univ-lemans.fr/theses/2005/2005LEMA1012.pdf.
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Braunwart, Paul R. "Uncovering and avoiding failure modes in driveline and tire/wheel NVH using a computational meta-model." Thesis, Massachusetts Institute of Technology, 2007. http://hdl.handle.net/1721.1/43099.
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Thesis (S.M.)--Massachusetts Institute of Technology, System Design and Management Program, 2007.<br>Includes bibliographical references (p. 105-110).<br>The automotive industry has undergone significant changes in recent years with increased competition and the introduction of new manufacturers into the market. With this changing market, a more efficient approach to Noise Vibration and Harshness (NVH) development is needed to foster better decisions and support the compressed product development timing required by the market.To address this, the "Slider Bar" process and meta-model are presented. Based on the failure mode avoidance approach, the process and model allow the engineering teams to uncover and avoid potential tire/wheel and driveline NVH failure modes. Therefore, early in the product development process, development teams can identify control and noise factor limits and system level effects, avoid potential NVH failure modes, and develop appropriate countermeasures.Using insights from innovation diffusion theory, the process and tool were deployed systematically to NVH community, with user insights used to adapt and improve the process and tools. Based on this work, a strategy is introduced for the development and adoption of a failure mode avoidance initiative.<br>by Paul R. Braunwart.<br>S.M.
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Aghaei, Shayan. "Acoustic Radiation Of An Automotive Component Using Multi-Body Dynamics." Thesis, KTH, Fordonsdynamik, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-288710.
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An important facet of creating high-quality vehicles is to create components that are quiet and smooth under operation. In reality, however, it is challenging to measure the sound that some automotive components make under load because it requires specialist facilities and equipment which are expensive to acquire. Furthermore, the motors used in testbeds drown out the noise emitted from much quieter components, such as a Power Transfer Unit (PTU). This thesis aims to solve these issues by outlining the steps required to virtually estimate the acoustic radiation of a PTU using the Transmission Error (TE) as the input excitation via multi-body dynamics (MBD). MBD is used to estimate the housing vibrations, which can then be coupled with an acoustic tool to create a radiation analysis. Thus, creating a viable method to measure the acoustic performance without incurring significant expenses. Furthermore, it enables noise and vibration analyses to be incorporated more easily into the design stage. This thesis analysed the sound radiated due to gear whine which arises due to the TE and occurs at the gear mesh frequency and its multiples. The simulations highlighted that the TE can be accurately predicted using the methods outlined in this thesis. Similarly, the method can reliably obtain the vibrations of the housing. The results from this analysis show that at 2000 rpm the PTU was sensitive to vibrations at 500, 1000 and 1500 Hz, the largest amplitude being at 1000 Hz. Furthermore, the Sound Power Level (SWL) was proportional to the vibration amplitudes in the system. Analytical calculations were conducted to verify the methods and showed a strong correlation. However, it was concluded that experiments are required to further verify the findings in this thesis.<br>En viktig aspekt i att skapa fordon av hög kvalitet är att skapa komponenter som är tysta och smidiga under drift. I verkligheten är det dock svårt att mäta ljudet som vissa fordonskompo- nenter ger under belastning eftersom det kräver specialanläggningar och utrustning, vilket är dyrt att skaffa. Dessutom maskerar motorerna som används i testbäddar ut bullret från mycket tystare komponenter, till exempel en kraftöverföringsenhet (PTU). Detta examensar- bete syftar till att lösa dessa problem genom att beskriva de steg som krävs för att virtuellt uppskatta den akustiska strålningen av en PTU med hjälp av transmissionsfelet (TE) som ingångsexcitation via flerkroppsdynamik (multi-body dynamics, MBD). MBD används för att uppskatta kåpans vibrationer, som sedan kan kopplas till ett akustiskt verktyg för att skapa en ljudutstrålningsanalys. Således skapas en genomförbar metod för att mäta den akustiska pre- standan utan att medföra betydande kostnader. Dessutom möjliggör det att lättare integrera ljud- och vibrationsanalyser i designfasen. Detta examensarbete analyserade ljudet som utstrålats på grund av kugghjulsljud, som uppstår på grund av TE och uppträder vid kuggingreppsfrekvensen och dess multiplar. Simuleringarna belyste att TE kan förutsägas exakt med de metoder som beskrivs i detta examensarbete. På samma sätt kan metoden på ett tillförlitligt sätt uppnå kåpans vibrationer. Resultaten från denna analys visar att vid 2000 rpm var PTU känslig för vibrationer vid 500, 1000 och 1500 Hz, den största amplituden var vid 1000 Hz. Dessutom var ljudeffektsnivån (SWL) proportionell mot vibrationsamplituderna i systemet. Analytiska beräkningar genomfördes för att verifiera metoderna och visade en stark korrelation. Dock drogs slutsatsen att experiment krävs för att ytterligare verifiera resultaten i detta arbete.
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Geoffriault, Maud. "Réduction active des vibrations et des bruits d'une machine électrique par la stratégie de commande." Thesis, CentraleSupélec, 2015. http://www.theses.fr/2015SUPL0003/document.
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Les travaux de cette thèse s’inscrivent dans le contexte du développement de groupes motopropulseurs électriques pour véhicules automobiles. Ces développements ont mis en lumière les problématiques liées aux phénomènes acoustiques et vibratoires des machines électriques, spécifiques à l'application automobile. L'objectif de ces travaux est la mise en place de lois de commande dédiées à la réduction d'harmoniques de courant à l'origine d'harmoniques vibratoires.Pour cela, les différents éléments du système ont été modélisés, puis les paramètres du modèle électrique de la machine ont été identifiés au moyen de mesures expérimentales.Deux stratégies de commande ont ensuite été développées puis mises en place. D'une part, un régulateur dédié à l'harmonique de courant visé a été synthétisé par optimisation H-infini. D'autre part, la modélisation de l'origine de cet harmonique comme provenant d'un signal perturbateur externe a permis la compensation de celui-ci au moyen d'un observateur.L'efficacité de ces deux stratégies sur la réduction des harmoniques de courant visés et des harmoniques vibratoires correspondants a été validée expérimentalement sur banc d'essai vibratoire<br>This work takes place in the context of the development of powertrains for electric vehicles. Those developments have raised new issues such as noise and vibrations of electrical machines, which are important issues in automotive applications. The aim of this thesis is to develop control laws dedicated to the reduction of currents harmonics that are responsible for vibration harmonics.In that purpose, different parts of the system have been modelled. Parameters of the electrical model of the studied machine have then been identified thanks to experimental measurements.Two different control laws are proposed and developed. One the one hand, a controller is synthetized thanks to H-infinity optimization. On the other hand, the studied current harmonic is modelled as coming from an external disturbance. This virtual disturbance is estimated thanks to an observer and compensated
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Park, Hyungjoo. "Development of a Test System to Measure Squeak Propensity of Vehicle Underbody Components." University of Cincinnati / OhioLINK, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1592135515122287.
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[Verfasser], Sarawut Lerspalungsanti. "Ein Beitrag zur Modellierung des menschlichen Komfortempfindens und Beurteilung der NVH-Eigenschaften in der Antriebsstrangentwicklung auf Basis von künstlichen neuronalen Netzen = Modeling of human sensation and evaluation of NVH-characteristic in the drive train development using method based on artificial neural networks / Sarawut Lerspalungsanti." Karlsruhe : IPEK, 2010. http://d-nb.info/1000897486/34.
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Shabani, Arber. "Human emotional response to automotive steering wheel vibration : development of a driver emotional semantic scale." Thesis, Brunel University, 2016. http://bura.brunel.ac.uk/handle/2438/13539.
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The 21st century automobile has become more than just a simple tool for transportation and more of a brand image or a way for drivers to express their personal taste. This has made it increasingly important for automotive manufacturers to design the driver experience and driver feeling so as to tailor their preferences and interests. Currently there is not enough information on how to design or brand the communication of meaningful feedback from the automobile to the driver. With the development of new advanced technologies such as electric steer-by-wire systems or electric automobiles, the need to provide meaningful feedback to the driver plays a central role in the experience of using the new driving technology. Thus it is important to understand how to assess the emotional response to the stimuli reaching the driver so to be able to optimise at later stage the perceived experience. Steering wheel vibration feedback plays an important role for the driver’s control input when driving. There is currently a lack of research on the formal assessment criteria of driver emotional response used to define automotive steering wheel vibration feedback, therefore this thesis proposes a newly Driver Emotional Semantic (DES) Scale to answer the research question: “How can the emotional response to steering wheel vibration be assessed?”. This study starts with a comparison of a questionnaire survey (Exp.1) and a laboratory test (Exp.2) to identify if a correlation exists between the emotional ratings measured from the expected driver’s perception of the vibration and the experienced emotional feeling of steering wheel vibration. The work then defines a semantic scale to capture the vibrational vocabulary used by the driver to express their feeling of perceived vibration during real-road driving scenarios. Experiment 3 was therefore carried out to gather the underlying semantic descriptors used by drivers during driving scenarios. To test the reliability of the descriptive pairs of the DES rating scale developed, two evaluations of the assessment criteria were carried out: in real road scenarios (Exp.4) and laboratory test setting (Exp.5). Current research findings of this thesis suggest that the consistency of the scale dimensions found in the field study has captured with greater accuracy the driver semantic experience of automotive steering wheel vibration character as compared to the laboratory experiment dimensionality. Results suggest that the main vibrotactile semantic descriptors to assess the human emotional response to automotive steering wheel vibration were found to be four: pleasant, smooth, sharp and powerful. The final proposed DES scale could help automotive research and industry determine and customise the aspects of the automobile towards drivers’ preferences of felt experience.
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Cameron, Christopher John. "Design of Multifunctional Body Panels in Automotive Applications : Reducing the Ecological and Economical footprint of the vehicle industry." Licentiate thesis, Stockholm : Skolan för teknikvetenskap, Kungliga Tekniska högskolan, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-10661.
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Schille, Fabian Martin [Verfasser], and A. [Akademischer Betreuer] Albers. "Methode zur generationsübergreifenden NVH-Optimierung des Wiederstartkomforts von Hybridfahrzeugen durch eine manöverbasierte Validierung auf dem Akustikrollenprüfstand = Method for an intergenerational NVH-optimisation regarding the restarting comfort of hybrid vehicles using a manoeuvre-based validation on the acoustic roller test bench / Fabian Martin Schille ; Betreuer: A. Albers." Karlsruhe : KIT-Bibliothek, 2021. http://d-nb.info/1235072436/34.
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Lerspalungsanti, Sarawut. "Ein Beitrag zur Modellierung des menschlichen Komfortempfindens und Beurteilung der NVH-Eigenschaften in der Antriebsstrangentwicklung auf Basis von künstlichen neuronalen Netzen." Karlsruhe IPEK, 2010. http://d-nb.info/1000897486/34.
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Otipka, Václav. "Konstrukční návrh zkušebního stavu s uzavřenou smyčkou toku momentu pro experimentální ověření parametrů převodových ústrojí." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2018. http://www.nusl.cz/ntk/nusl-378013.
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The thesis deals with the design of the experimental testing rig. Test rig is designed to measure NVH transmission parameters. First, basic knowledge of vibro-acoustic measurement is discussed. This is followed by an evaluation of the most commonly used power devices to derive real loads on measured gearboxes. In more detail, a back-to-back test rig is disassembled among other things. In the thesis are described two main components, which are composed of a connecting element and a test bench. Both components were optimized during the design due to their modal properties. Numerical modal analysis was performed in ANSYS Workbench software. The thesis also includes strength calculations performed using both numerical and analytical approaches. The indispensable result of the design work is the complete drawing documentation. Finally, measurements of vibrations and noise on the physically made connecting element assembly have been performed and subsequently evaluated.
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Ravi, Vinay. "Effect of nonlinear chamber compliance and pumping areas on the dynamic stiffness and chamber pressure of a hydraulic body mount." The Ohio State University, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=osu1532032639331273.
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Kernstock, Thomas [Verfasser], and A. [Akademischer Betreuer] Albers. "Ein Beitrag zur gezielten Reduktion des NVH-Phänomens Getrieberasseln über den gesamten Fahrzeugentwicklungsprozess am Beispiel eines Doppelkupplungsgetriebes = A contribution to the targeted reduction of the NVH phenomenon gear rattle during the entire vehicle development process at the example of a dual clutch transmission / Thomas Kernstock ; Betreuer: A. Albers." Karlsruhe : KIT-Bibliothek, 2021. http://d-nb.info/1235072533/34.
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Xie, Yuan. "Investigation on Road Noise Transmission through Steering System." Thesis, KTH, MWL Marcus Wallenberg Laboratoriet, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-224153.
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An investigation on noise transmission through the steering gear system is focused on the area of vehicle NVH (Noise Vibration and Harshness). From previous investigations it is well known that noise transmission through the steering system sometimes has a significant influence referring to tire road noise. In these cases, the interface force between steering gear and vehicle subframe is usually of interest during early stages of vehicle development. The target of the current work is to validate an approach based on a method, commonly known as the “Blocked force method” for noise and vibration testing, and check if it is possible to estimate the interface forces based on this method. This method became popular for mechanical testing in the middle 1900s [1] [2] [3], because of its easy applicability. The basic idea is to fix the component on a rigid plate and measure the interface force at the coupling points with force transducers inserted in between. It has a considerable potential in practical use, because if the blocked force could provide a good estimation for the interface force in noise transmission, it enables an efficient measurement of critical NVH behaviors without having to resort to the complete vehicle.However intuitively, the blocked force data could not be used directly. As a result, a coupled system equation is used for the coupling of the steering gear and the car body. Both the inertance of car body and steering system are taken into account, and thus introduces a compensation for the difference between vehicle and test bench. The method is validated against the transfer function measured on the full vehicle as the reference and compare this with the result calculated with the measured “Blocked force” data. Siemens Test.Lab is used for data acquisition and first data processing. Matlab is used for data post processing. Matrix symmetrization and singular value truncation is used to deal with the ill-conditioned data of steering gear inertance. A hybrid model with Finite Element data is proposed. Two test conditions are investigated: one set is with rigid coupling and the other is decoupled with rubber.
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Palathamveed, Naqash. "Acoustic behavior of intake manifolds under tip-in and steady flow conditions an experimental investigation /." Columbus, Ohio : Ohio State University, 2008. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1199738161.
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Venezia, James J. Jr. "Vibration Modeling and Experimental Analysis of a Locomotive Cab." Thesis, Virginia Tech, 1997. http://hdl.handle.net/10919/36725.
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This study evaluates noise and vibrations in a heavy freight locomotive cab, and
provides several measures for providing more comfort to the crew. A full-scale
production cab and sill structure is used to provide the results. The cab is setup in a
controlled laboratory environment in a manner similar to the installation on a
locomotive. Field measurements are used to emulate actual vibration input to the
cab structure. A 16-channel data acquisition system is used to collect both noise and
vibration data on various parts of the cab structure and inside the cab. Upon
establishing the baseline for laboratory vibration measurements and correlating
them with field data, a design of experiment was conducted to evaluate the vibration
contribution of various parts of the cab. This showed that the cab floor and cab roof
had the largest vibrations. A series of solutions including stiffening the cab floor
and damping the cab roof were investigated. The results showed that although such
solutions reduce localized vibrations, the overall effect on reducing cab interior
noise is minimal. As a more global solution, the cab was isolated from the sill
structure through six elastomeric elements mounted at the base of the cab and at the
crash post. The mounts at the base were selected such that they support the static
weight of the cab, provide a resonance frequency that is below the excitation range,
and offer good lateral and longitudinal stability. Two tube-form elastomeric mounts
were placed between the cab structure and the crash posts which attach to the front
of the sill structure. The test results showed that the soft-mounted cab had
significantly lower noise and vibration than the original cab. The vibration levels
were reduced 10 to 100 times at certain locations and frequency ranges. The overall
noise level was reduced by approximately 6 dBA. In an attempt to provide an
estimate of effectiveness of the mounts with different stiffness values, a simulation
model was prepared in Matlab. Although the model did not yield accurate results, it
resulted in several recommendations for future research work.<br>Master of Science
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Tang, Jinghan. "Finite element modelling of ventilated brake disc hot spotting." Thesis, University of Bradford, 2017. http://hdl.handle.net/10454/13340.
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Hot spotting of automotive disc brakes is an undesired thermal localisation phenomenon, which is a challenge for numerical modelling in terms of both accuracy and efficiency especially for complex disc geometry. In this research, the aim was to develop a computationally efficient finite element (FE) approach for 2-piece pin-mounted ventilated disc hot spot prediction with acceptable accuracy enabling parametric studies to contribute to the knowledge of the complex mechanisms. A time reduction strategy for the simulations was established by incorporating an axisymmetric brake pad assumption with material scaling factor and the friction characteristics were defined by a user-subroutine. The computing accuracy and efficiency of this method were then verified by comparing with traditional FE models. 2D in-plane, 2D out-of-plane, and 3D models were performed to investigate the effects of ventilated disc hot spotting, radial hot spot/band migration, and hot spotting of realistic complex disc geometry respectively. Both 2D and 3D results were validated using experimental results based on a laboratory dynamometer and showed good correlation. The results suggested that adequate modelling of friction pair contact pressure distribution and the subsequent non-uniform heat generation is essential for hot spot simulation; speed was identified as the determinant for the number of hot spots, whereas hot spot temperature was determined by energy level. Furthermore, recommendations for vent design, pins, disc run-out, cooling, material selection, wear rate, pad length and loading distribution were given. Finally, hot spotting and hot band migration cause-effect chains were established based on the results and discussion.
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MATUSZEWSKI, MATEUSZ JACEK. "Auralization of noise sources to support interior car sound design." Doctoral thesis, Università Politecnica delle Marche, 2017. http://hdl.handle.net/11566/250177.
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Attualmente i maggiori produttori nel settore automotive cercano di sostituire i tradizionali motori a combustione interna con unità elettriche. Ne consegue che, essendo questi sistemi propulsivi molto meno rumorosi dei loro “colleghi” a combustione, essi influenzano non poco il confort acustico all’interno dell’abitacolo, in quanto rumorosità che prima non venivano percepite a causa dell’effetto “maschera” prodotto dal motore, risultano ora particolarmente di disturbo. Il “wind noise” è considerato, tra queste, quello più critico in termini di impatto sulla percezione dell’acustica dell’abitacolo da parte dei passeggeri. Lo studio di come queste “nuove” sorgenti di rumore possano influire su una sensazione di comfort acustico per gli occupanti dell’autovettura viene oggigiorno effettuato con tecniche di auralizzazione, in quanto offrono la possibilità di effettuare modifiche virtuali dell’acustica di una qualsiasi cavità, senza dover modificare realmente l’ambiente.
La presente tesi vuole proporre un nuovo metodo di auralizzazione, specifico per l’ambito automotive, che sia in grado di riprodurre, con elevata fedeltà, il wind noise. Il metodo proposto consente di effettuare un’auralizzazione del wind noise senza la necessità di avere informazioni sulla geometria interna dell’abitacolo dell’autovettura oggetto di studio. L’approccio si basa su un modello statistico che tiene conto di alcuni parametri chiave della Room Impulse Response (RIR) associata alla cavità e delle “prime riflessioni” (early reflections). Dal momento che la qualità di una procedura di auralizzazione dipende, però, anche dal set di Head Related Trasfer Functions (HRTFs) usato, viene proposto un approccio per la misura e il processing di HRTFs specifiche per le cabine di autoveicoli. Oltre a ciò, poiché è importante definire quante riflessioni sono effettivamente necessarie per garantire una corretta e realistica riproduzione della rumorosità percepita all’interno dell’abitacolo, viene presentato uno studio sul corretto utilizzo della RIR. L’ultimo punto trattato nella presente tesi di dottorato consiste in un’analisi, da un punto di vista “human-oriented”, dell’accuratezza minima necessaria con cui, laddove il fine ultimo è l’auralizzazione delle rumorosità identificate, tecniche di localizzazione di sorgenti acustiche riescono a rilevare la presenza di un rumore. Il motivo di un tale studio è legato alla necessità di capire quale sia la capacità di distinguere rumori provenienti da direzioni differenti da parte degli occupanti di un’autovetttura e, soprattutto, di effettuare analisi di tipo “what-if”.
Globalmente, quanto presente in questa tesi vuole rappresentare una soluzione integrata, economica ma efficace, per approcciare il problema dell’auralizzazione all’interno dell’abitacolo di un autoveicolo.<br>Current trend in the automotive industry is to replace “traditional” internal combustion engines into electrical units. As a result, cars are becoming quieter, which brings sound sources originally masked by combustion engines to the top. One of the most industrially important “new” sources is wind noise. Performing investigation on sounds, especially on those which cannot be measured separately, require sophisticate methods, like auralization. This thesis is mainly focused on the development of a new time-saving auralization method, tailored for car interior applications, which preserve sufficient fidelity in terms of wind noise reproduction. The proposed method aims to make it possible to auralize wind noise without any prior knowledge of the geometry of the car under investigation. This goal is achieved by using a statistical model of key Room Impulse Response (RIR) parameters and early reflections. Quality of sound auralization highly depends on Head-Related Transfer Functions (HRTFs) used. A new approach for measuring and processing HRTFs targeted at auralizing sound in car cabins is proposed. The remaining question is to understand how many reflections are effectively needed for providing a realistic listening experience. Therefore Investigations on Room Impulse Response modifications are included in the thesis. Also a human-oriented approach to define the minimum accuracy required for source localization techniques when used in car interiors is presented. By exploiting sound source localization and separation it becomes possible to virtually relocate sources and to perform what-if analyses. The proposed approach for in-vehicle auralization can be a substantial economic benefit for car manufactures considering the high costs of wind tunnel tests.
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Gautam, Prashanta. "Investigation of air-borne noise generation mechanisms in tire noise." University of Akron / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=akron148552634330808.
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Fürich, Adam. "Optimalizace skříně převodovky pro elektrická vozidla z ohledem na vyzařovaný hluk." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2021. http://www.nusl.cz/ntk/nusl-449782.
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This thesis deals with the vibration and noise of the gearbox for an electric vehicle. The gearbox itself acts as an emitter of unwanted noise caused by vibration excitation of the internal components of the gearbox. It is therefore necessary to deal with a complex unit such as the gearbox at system level as soon as it is being designed. This can be achieved using analytical tools and software. In this thesis, in order to evaluate the validity of the designed gearbox, a procedure is developed using both technical experiment and numerical simulations. The effect of the bolt preload is not overlooked for the following computational modelling dealing with the radiated noise of the gearbox. The results obtained from the performed technical experiments were then evaluated and compared with the results of the computational models. In this way, it is possible to compare the different approaches, their limitations and weaknesses. Furthermore, the thesis deals with design modifications that are analyzed using computational modeling. The thesis is concluded with a brief description of the application of each approach and an evaluation of the gearbox design modifications.
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Lochmahr, Marco [Verfasser], and A. [Akademischer Betreuer] Albers. "Methode zur interdisziplinären Analyse und Optimierung von Hinterachssystemen im Spannungsfeld Fahrdynamik, Fahrkomfort und NVH am Beispiel der Raumlenkerachse und des Teilsystems Fahrschemellager im Kontext XiL = Interdisciplinary analysis and optimization of rear axle systems in the conflict of driving dynamics, riding comfort and NVH using the example of independent multilink axle and subframe bushing in the context of XiL / Marco Lochmahr ; Betreuer: A. Albers." Karlsruhe : KIT-Bibliothek, 2021. http://d-nb.info/1235072452/34.
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Gnanakumarr, Max Mahadevan. "Integrated investigation of impact-induced noise and vibration in vehicular drivetrain systems." Thesis, Loughborough University, 2004. https://dspace.lboro.ac.uk/2134/11575.
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This thesis highlights one of the most significant concerns that has preoccupied drivetrain engineers in recent times, namely drivetrain clonk. Clonk is an unacceptable audible sound, which is accompanied by a tactile drivetrain response. This may occur under several different driving conditions. Many drivetrain NVH concerns are related to impact loading of subsystems down-line of engine. These concerns are induced by power torque surge through engagement and disengagement processes, which may propagate through various transmission paths as structural waves. The coincidence of these waves with the acoustic modes of sub-system components leads to audible responses, referred to as clonk. The approach usually undertaken and reported in literature is either purely theoretical or constitutes experimental observation of vehicle conditions. A few research workers have reported rig-based investigations, but not under fully dynamic conditions with controlled and reproducible impulsive action. The research reported in this thesis combines experimental and numerical investigation of high frequency behaviour of light truck drivetrain systems, when subjected to sudden impulsive action, due to driver behaviour. The problem is treated as a multi-physics interactive phenomenon under transient conditions. The devised numerical method combines multi-body dynamics, structural modal analysis, impact dynamics in lash zones and acoustic analysis within an overall investigation framework. A representative drivetrain system rig is designed and implemented, and controlled tests simulating driver behaviour undertaken. The combined numerical predictions and experimental noise and vibration monitoring has highlighted the fundamental aspects of drivetrain behaviour. Good agreement is' also found between the detailed numerical approach and the experimental findings. Novel methods of measurement such as Laser Doppler Vibrometery have been employed. Simultaneous measurements of vibration and noise radiation confirm significant elasto-acoustic coupling at high impact energy levels. One of the major finds of the thesis is the complex nature of the clonk signal, being a combination of accelerative and ringing noise, with the latter also comprising of many other lower energy content as observed in the case of transmission rattle and bearing-induced responses. Therefore, the link between rattle and clonk, long suspected, but not hitherto shown has been confirmed in the thesis. Another major find of particular commercial interest is the insignificant contribution of torsional damping devices such as dual mass flywheels upon the accelerative component of the clonk response.
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Xue, Boyu. "3D Printed Lattice Structure for Driveline Applications." Thesis, KTH, Materialvetenskap, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-299270.
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Lattice structures have received a lot of attention as cellular materials in recent years because of their outstanding properties, such as high strength-to-weight ratio, heat transfer, energy absorption, and capability of improving noise, vibration and harshness (NVH) behavior. This type of structure received a boost from additive manufacturing (AM) technology, which can fabricate geometries in practically any shape. Due to economic and environmental requirements, lightweight design is increasingly used in automobile and construction equipment applications. NVH behavior is a crucial issue for construction equipment. However, the conventional structures' NVH behavior is mainly decided by the mass, so silence often requires heavy systems, leading to more energy consumption and emission. Therefore, the environmental trends and the resulting economic competition have limited traditional (heavy) solutions to improve NVH behavior and make the lightweight design more difficult. Novel solutions are necessary to light the difficulty and challenge of combining NVH and lightweight requirements. In this research, topology optimization was implemented on a New Articulated Hauler Transmission (NAHT) component to balance lightweight and NVH behavior. The topology- optimized 3D model was filled by a non-homogenous lattice structure with optimal lattice density via size optimization. Lattice structure optimization is one type of topology optimization, and it is the term for describing these procedures. To fabricate the complicated lattice structure, additive manufacturing (or 3D printing) is required (after topology and lattice structure optimization). The new models were analyzed using the finite element method (FEM), and the results of the analysis were compared with those of the original models. After the comparison, positive results were obtained, demonstrating that topology and lattice optimization can be applied in the design of construction equipment components. According to the results, lattice structure optimization can create a reliable lightweight design with good NVH behavior. Furthermore, lattice structure's organization and layout have a significant impact on the overall performance.<br>Gitterstrukturer har fått mycket uppmärksamhet som cellulära material under de senaste åren på grund av deras enastående egenskaper, t.ex. hög hållfasthet i förhållande till vikt, värmeöverföring, energiabsorption och förmåga att förbättra buller-, vibrations- och bullerskador (NVH-beteende). Denna typ av struktur har fått ett uppsving av tekniken för additiv tillverkning (AM), som kan tillverka geometrier i praktiskt taget vilken form som helst. På grund av ekonomiska och miljömässiga krav används lättviktsdesign i allt större utsträckning inom bilindustrin och byggnadsutrustning. NVH-egenskaperna är en viktig fråga för anläggningsutrustning. De konventionella konstruktionernas NVH-beteende bestäms dock huvudsakligen av massan, vilket innebär att tystnad ofta kräver tunga system, vilket leder till ökad energiförbrukning och större utsläpp. Miljötrenderna och den ekonomiska konkurrens som följer av detta har därför begränsat de traditionella (tunga) lösningarna för att förbättra NVH-egenskaperna och gjort lättviktsdesignen svårare. Nya lösningar är nödvändiga för att lösa svårigheten och utmaningen med att kombinera NVH- och lättviktskrav. I den här forskningen genomfördes topologioptimering på en komponent för en ny ledad transportörtransmission (NAHT) för att balansera lättvikts- och NVH-beteende. Den topologioptimerade 3D-modellen fylldes med en icke-homogen gitterstruktur med optimal gittertäthet via storleksoptimering. Gitterstrukturoptimering är en typ av topologioptimering, och det är termen för att beskriva dessa förfaranden. För att tillverka den komplicerade gitterstrukturen krävs additiv tillverkning (eller 3D-utskrift) (efter topologi- och gitterstrukturoptimering). De nya modellerna analyserades med hjälp av finita elementmetoden (FEM), och resultaten av analysen jämfördes med resultaten av de ursprungliga modellerna. Efter jämförelsen erhölls positiva resultat, vilket visar att optimering av topologi och gitterstruktur kan tillämpas vid utformning av komponenter för byggutrustning. Enligt resultaten kan optimering av gitterstrukturen skapa en tillförlitlig lättviktsdesign med bra NVH-beteende. Dessutom har gitterstrukturens organisering och layout en betydande inverkan på den totala prestandan.
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De, la Cruz Miguel. "The influence of transient thermo-elastohydrodynamic conjunctions on automotive transmission rattle." Thesis, Loughborough University, 2011. https://dspace.lboro.ac.uk/2134/8042.
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Automotive transmission rattle is the noise generated due to impacts between manual transmissions meshing gear teeth in the presence of backlash. It is considered to be a Noise, Vibration and Harshness (NVH) phenomenon and is originated due to combustion irregularities (engine order vibrations), especially in diesel vehicles. This thesis focuses in the case of creep rattle for the MMT6 Ford Getrag transmission (six speeds plus reverse) with a DW10b, 4-cylinder, 4-stroke, 2.0 litres diesel engine. This particular rattle condition is fundamentally similar to any other where an engaged gear is pertained (drive, over-run or float), with the 1st or 2nd gear engaged at a very low engine speed. The numerical models include an initial single degree of freedom (DoF) simulation. It comprises either of the engaged gear pair under Hertzian contact conditions or of a loose gear pair under hydrodynamic regime of lubrication. Once the validity of this model is established and correlated with the results obtained from a single gear pair test rig, simulations of increasing complexity can be envisaged. A 7 DoF numerical model is, therefore, developed. The Hertzian contact model still prevails for the engaged gear pair, whereas an analytical hydrodynamic solution is implemented for the remaining 6 loose gear wheels and Petrov s law is applied to the needle bearings retaining the gear wheels. With the aim of accommodating a fully lubricated model of all the tribological conjunctions, an analytical elastohydrodynamic (EHL) Grubin type algorithm is employed. Also, the energy equation is analytically solved for hydrodynamic and elastohydrodynamic conjunctions, based on the assumptions dictated by the Peclet number. Therefore, under hydrodynamic conditions, the energy equation is governed by viscous heating and convective cooling, whereas in the EHL conjunctions the governing terms are viscous and compressive heating, together with conductive cooling. The retaining needle bearings follow the same heat generation mechanism as journal bearings. The effective viscosity, as obtained from the Houpert s equation accounting for pressure and thermal effects, is fundamental for the study of the friction in the contact. The hydrodynamic contacts are only governed by viscous friction, whereas EHL conjunctions exhibit asperity iv interactions as well as viscous effects. The results obtained from this new 7 DoF model are then compared to the experimental measurements taken from the vehicle tests and various purpose-built drivetrain rigs. A metric named Impulsion Ratio is hereby introduced, aiming to shed some light into the predictions obtained by the various models presented. This metric is the ratio of driving over resistive forces acting on each individual gear wheel. Its use is tested to predict single or double-sided rattle scenarios and, therefore, ascertaining higher and lower rattle levels. The 13 DoF model from which these conclusions were obtained includes shafts planar translation and rocking moments. The rolling element bearings supporting the shafts are, therefore, modelled to capture the inherent frequencies arising from their motion. The final model introduces the effects of transient thermo-elastohydrodynamics. This 7 DoF dynamic model accounts for a numerical solution of Reynolds equation with Elrod s cavitation algorithm for simultaneous teeth in mesh. The results obtained validate the previously used Grubin assumption by comparing the predicted central film thickness along the full mesh of one tooth. Also, the effect of starved input conditions and thermal and isothermal solutions are studied.
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Reis, Danilo Bruneli. "Posicionamento de \"Deadeners\" para a redução de vibração em estruturas veiculares via sensibilidade inerente." Universidade de São Paulo, 2008. http://www.teses.usp.br/teses/disponiveis/18/18149/tde-21032018-153547/.
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O desempenho acústico em um veículo é fortemente dependente da interação fluido-estrutura entre o ar no habitáculo do veículo e a estrutura metálica. A maioria dos problemas de ruído e vibração relacionados a esta interação provem dos picos de ressonância da chapa metálica, quando excitada por forças externas (pista, motor, vento). A redução dos picos de ressonância pode ser obtida através da aplicação de placas asfálticas (\"Deadeners\") na estrutura. O problema está no posicionamento das placas, que usualmente é realizado experimentalmente por tentativa e erro. Este trabalho propõe o uso da sensibilidade inerente para o posicionamento de \"Deadeners\" em estruturas metálicas veiculares, em particular no teto do veículo. As funções de resposta em freqüência (FRFs) do teto são obtidas experimentalmente e processadas adotando a técnica da sensibilidade inerente, obtendo assim a sensibilidade dos picos de ressonância e identificando os locais passíveis de instalação de \"Deadeners\". Como resultado da análise, é possivel localizar a posição ótima para o \"Deadener\" que maximizará a redução de picos de resonância de interesse. Após o posicionamento dos \"Deadeners\", foi possível verificar a atenuação dos picos de ressonância no teto do veículo, mostrando a eficácia do método utilizado. A maior vantagem do método é que este requer apenas medições de resposta em frequência do sistema original, sem necessidade de modificações na estrutura do veículo para obter a sensibilidade do sistema a modificações.<br>The Noise Vibration and Harshness (NVH) performance of passenger vehicles strongly depends on the fluid-structure interaction between the air in the vehicle cavity and the sheet metal structure of the vehicle. Most of noise and vibration problems related to this interaction come from resonance peaks of the sheet metal, which are excited by external forces (road, engine, wind). A reduction of these resonance peaks can be achieved by applying deadeners in the sheet metal. The problem is where these deadeners shall be fixed, which is usually done in a trial-anderror basis. In this work, one proposes the use of embedded sensitivity to locate the deadeners in the sheet metal of the vehicle, more specifically in the vehicle roof. Experimental FRFs of the roof are obtained and data is processed by adopting the embedded sensitivity method, thus obtaining the sensitivity of the resonance peaks on the local increase of stiffness due to the deadeners. As a result, by examining the sensitivity functions, one can find the optimum location of the deadeners that maximize their effect in reducing the resonance peaks of interest. After locating the deadeners in the optimum positions, it was possible to verify a strong reduction in resonance peaks of the vehicle roof, thus showing the efficiency of the procedure. The main advantage of this procedure is that it only requires FRF measurements of the vehicle in its original state, not needing any previous modification of the vehicle structure to find the sensitivity functions.
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Wang, Shuo. "Control of a Uni-Axial Magnetorheological Vibration Isolator." University of Toledo / OhioLINK, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1302200947.
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Melo, Fábio Xavier de. "Análise de caminhos de transferência de energia no projeto de sistemas de controle." Universidade de São Paulo, 2013. http://www.teses.usp.br/teses/disponiveis/18/18149/tde-23092013-170034/.
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A análise de caminhos de transferência de energia (TPA na sigla em inglês para Transfer Path Analysis) corresponde a um grupo de métodos numérico/experimental para análise e solução de problemas vibro-acústicos de sistemas lineares invariantes no tempo, sendo seu principal campo de aplicação a indústria automotiva. A TPA é uma técnica que identifica as principais fontes de vibração e ruído, e os caminhos estruturais e acústicos pelos quais são transmitidas para determinados locais de interesse. Conhecendo as fontes de ruído e vibração e os caminhos de propagação é possível propor modificações eficientes em minimizar o ruído/vibração nas regiões de interesse, ou atribuir características desejáveis para tais componentes, envolvendo técnicas de controle passivo e ativo. Este trabalho apresenta um estudo numérico e experimental das técnicas de TPA, utilizando métodos diretos e inversos de determinação de forças operacionais. Estes estudos foram realizados em um mockup de um veículo, com o objetivo de determinar o caminho de maior contribuição para o ruído no interior do protótipo, e a partir deste resultado, propor um sistema de controle ativo para minimizar este ruído interno.<br>The Transfer Path Analysis (TPA) is a group of numerical/experimental tools for the analysis and troubleshooting of noise and vibration problems in linear time invariant vibroacoustic systems, being the automotive sector its major user. TPA consists of a numerical/experimental analysis that allows the identification of the main noise and vibration sources and the structural/acoustic transfer paths to the Target points. Based on the sources and paths, it is possible to propose modifications that efficiently minimize noise and vibration at the target positions. By means of active control it is possible to modify noise and vibration in order to change, rather than minimize noise and vibration, achieving certain design targets. This work presents a numerical and experimental study of TPA techniques, using direct and inverse operational loads determination methods. These studies were performed on a vehicle mockup, in order to determine the path of greatest contribution to the noise inside the prototype, and from this result, propose an active control system to minimize this internal noise.
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VETTORELLO, ANDREA. "Sviluppo di una metodologia numerica per la riduzione del rumore nella cavità acustica in veicoli ad alte prestazioni." Doctoral thesis, Università degli studi di Modena e Reggio Emilia, 2022. http://hdl.handle.net/11380/1277105.
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La descrizione e l’abbattimento del rumore entro l’abitacolo di un veicolo rappresenta un aspetto rilevante della delibera dello stesso, tale esigenza è stata enfatizzata di recente a seguito della diffusione di veicoli dotati di power-unit elettriche. La descrizione del rumore richiede la conoscenza della sua sorgente e delle sue modalità di propagazione dalla sorgente sino al ricevente, ovvero sino all’apparato uditivo degli occupanti il veicolo. La propagazione del rumore, in genere, avviene: o per vibrazione dei sottosistemi strutturali del veicolo, che rappresentano la funzione di trasferimento tra sorgente e ricevente, o tramite via aerea.
Per conoscere in modo attendibile le caratteristiche acustiche di un veicolo è necessario che siano presenti tutti i componenti caratterizzanti, vale a dire tutti i componenti che determinano il comportamento modale del sistema. Lo studio del rumore avviene sia sperimentalmente, sia attraverso modelli di simulazione CAE applicati ad un veicolo in allestimento Trimmed-Body (TB).
Il TB definisce la cavità acustica come il volume d’aria racchiuso all’interno dell’abitacolo in cui si investigano i fenomeni di rumore. Si discretizza la cavità acustica mediante Elementi Finiti solidi e attraverso l’impostazione di analisi multi-fisiche fluido-struttura di risposta in frequenza si ricostruisce l’andamento delle funzioni di trasferimento del rumore (NTF). Da tali analisi è inoltre possibile valutare la partecipazione dei principali componenti vibranti e i relativi modi propri di vibrare percepiti dall’orecchio umano entro la cavità. Si possono quindi dedurre ed implementare opportuni accorgimenti o per la risoluzione di eventuali problemi, o di miglioramento del progetto ove ampi margini di sicurezza siano evidenziati.
Durante lo sviluppo di un nuovo veicolo, quindi, le prestazioni acustiche sono note solamente ad uno stadio piuttosto avanzato del progetto, in cui molti componenti del telaio sono di fatto già stati deliberati, e quindi non più modificabili. Qualora, durante campagne sperimentali preliminari, si riscontrino livelli di rumore al di sopra dei target prestabiliti, il margine di modifica progettuale lasciato alla risoluzione di tali problemi risulta quindi esiguo. Inoltre, per la grande complessità del sistema in analisi non risulta immediata l’identificazione delle cause di rumore e quindi talvolta viene investigato mediante l’approccio metodologico di tipo trial-and-error.
Questo lavoro di tesi, invece, si pone l’obiettivo di definire una metodologia CAE che riesca a prevedere l’insorgenza di rumore indesiderato e trasmesso per via strutturale sin dalle prime fasi di definizione di un nuovo veicolo, vale a dire in fase di concept del Body-in-White (BiW). Lo studio considera la potenza irradiata (ERP) da componenti che vengono posti in vibrazione come strumento per discriminare i componenti che possono essere maggiore causa di rumore in abitacolo. Il legame tra la vibrazione di componenti strutturali e la perturbazione del campo di pressione del fluido che bagna tali componenti, offre la possibilità di svincolarsi dalla necessità di simulare la cavità acustica e ragionare quindi in termini di ERP e ricavare le funzioni di trasferimento approssimate direttamente da modelli vettura in configurazione BiW. Grazie alla tempestiva identificazione dei componenti problematici, sono proposte tecniche di ottimizzazione numerica volte al conseguimento dei target prestazionali nell’ottica di una diminuzione del tempo richiesto per lo svolgimento dei calcoli se comparata al metodo trial-and-error convenzionalmente applicato. Questa metodologia offre la possibilità di sviluppare un modello TB con un migliorato livello di comfort acustico diminuendo il tempo di sviluppo di un nuovo veicolo.<br>In recent years, the description and reduction of noise in the passenger compartment have become an increasingly central aspect in the automotive field, especially for the spread of vehicles equipped with electric power units. The description of this dynamic phenomenon requires the identification of the source of the noise and its propagation paths to the receiver, which is usually the ears of the driver and the occupants of the vehicle. Generally, noise propagates either via air, or through the vibration of the vehicle's structural subsystems, which represent the transfer function between source and receiver. All the components that determine the modal behaviour of the system must be included in the simulation model to obtain the acoustic characteristics of the vehicle. Therefore, the study of these phenomena takes place experimentally and through simulation models on a Trimmed-Body (TB). The acoustic cavity may be defined as the air volume within the passenger compartment, in TB configuration of the vehicle. Finite Element analyses consent to reconstruct the trend of the noise transfer functions (NTF) through fluid-structure frequency response analysis. From these analyses, it might also be evaluated the participation factors of the vibrating components with relative modes to the noise at the ear inside the cavity. The results allow the appropriate measures to be devised to solve any noise problem.
Thus, in the development of a new vehicle, the noise performance is only evaluated at the final stages of the project, in which many components are already established and no longer adjustable. If noise levels do not meet the desired targets, restricted modifications to the project can be adopted to solve the issues. Furthermore, the identification of the causes of the noise could be a costly process due to the great complexity of the system.
This thesis aims to define a CAE methodology that aims to predict problems related to in-borne noise since the earliest stages of development of a new vehicle, i.e., in the definition phase of the so-called Body-in-White (BIW) layout.
The proposed study is based on the analysis of the radiated power (ERP) of vibrating components as a tool to discriminate the components likely to cause most of the noise in the passenger compartment. The link between the vibration of structural components and the perturbation of the pressure field of the fluid that wets these components offers the possibility of freeing oneself from the modelling of the acoustic cavity, and approaching the problem in terms of radiated power, therefore simulating approximate transfer functions directly on Body-in-White models.
Once the problematic components are identified, numerical optimization techniques are proposed to meet the performance targets, reducing the number of calculations required by conventional methods (e.g. trial and errors loops). The main tool in these analyses is Finite Element Simulation.
This methodology offers the possibility of developing a Trimmed-Body model with an improved level of acoustic comfort by reducing the development time of a new vehicle.
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Ivanič, Michal. "Návrh testovacího stavu diferenciálu pro zástavbu v bezdozvukové komoře." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2020. http://www.nusl.cz/ntk/nusl-432503.
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The diploma thesis describes the design of a test stand for experimental determination of vibroacoustic parameters of a part of the powertrain system. Thesis contains a research part, describing the problems of the drive system, vibroacoustics, measuring devices and also the division and the description of test stands. At the same time, the reasons for choosing a closed loop test stand are explained. Thesis also includes the results of analytical calculations and numerical results of FEM methods performed using ANSYS software, as well as drawing documentation of individual parts.
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Bala, Srujeeth Khanna. "Estimation of Blocked Forces in an Assembly with Rear Drive Unit as a Source." Thesis, KTH, Maskinkonstruktion (Inst.), 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-302780.
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Experimental validations are widely used for studying dynamic structural behaviors and these studies involve defining the structures completely as being used in real time. While in numerical simulations such detailed features are not specified to ease the computation, thereby deviating from accurate results. Hence experimental validations are more desired in product developments process. Applications of experimental verification for noise and vibration (referred to as NVH inautomotive industry) are expanding over the last few decades. Researchers are exploring ways to predict the responses on the new receiver using receiver independent forces, which led to evolution of component based TPA (Transfer Path Analysis) concept. The Component based TPA concept is an important development in automotive industry. It allows the auto manufacturers to make use of their available subsystems (like motor or a gearbox) in their newly developing vehicles. This has been made possible by defining the dynamic forces exerted by the source independent of receiving structure, which are then used to predict the responses on the new receiver. Evaluation of such receiver independent forces allows measurements to be made in a test rig rather than in the vehicle. This indeed helps in better communication between different departments or between suppliers and vehicle manufacturers, saves design iterations and time, and would help vehicle manufactures to predict the vehicle structural behaviors much before the first prototype is made. The method is based on the international standard ISO 20270:2019 (en) Acoustics – Characterization of sources of structure-borne sound and vibration – indirect measurement of blocked forces. The thesis is based on evaluating the source characterized forces that are used for predicting responses on a new receiving structure. For this, different methods in TPA are explored and for the rear drive unit application, in-situ method is chosen. The source characterized forces also termed as blocked forces are computed in different test set up and a validation check is performed. The obtained results are also compared with FEM and useful conclusions are drawn. And finally contact forces evaluated by integrating the subsystems are compared to the contact forces derived from the source characterized forces.<br>Experimentell verifiering av dynamiska krafter och vibrationer som uppkommer i fordon innebär mätning av tids-, frekvens- och/eller varvtalsberoende kvantiteter. Numeriska beräkningar har utvecklats till en hög nivå, men kan ännu inte beskriva alla förlopp och detaljer som förekommer i de verkliga processerna. På grund av detta krävs det fortfarande mätningar som en del av produktionsutvecklingen. Valideringsmetoder för ljud och vibrationer har utvecklats mycket desenaste decennierna, och ett mål har varit att utveckla mätmetoder där de uppmätta krafterna från en komponent som bidrar till buller kan mätas på ett sätt som inte beror på den testrigg eller det fordon den mäts i. Komponentbaserad TPA Transfer Path Analysis är en analysmetod som är viktig inom fordonsindustrin. Den gör det möjligt för en tillverkare att använda modeller av existerande komponenter (t.ex. motorer eller växellådor) i modeller för nya fordon. En grundläggande förutsättning är att de krafter som mäts är oberoende av den mottagande strukturen, det vill säga fordonet. Om krafterna är oberoende av strukturen där de mäts innebär det att komponenten kan mätas i en test rigg på ett annat ställe (till exempel hos en underleverantör) och att tillgång till fordon inte krävs för karaktäriseringen. Det underlättar kommunikationen mellan olika delar av organisationen och mellan underleveratörer och tillverkare och bidrar till att prediktera ljud och vibrationer innan den första prototypen är tillgänglig. Den föreslagna metoden är baserad på den internationella normen ISO 20270:2019 (en) Acoustics – Characterization of sources of structure-borne sound and vibration – indirect measurement of blocked forces. Examensarbetet handlar om att utveckla en mätmetod för att kunna ta fram krafter genererade av komponenter som är oberoende av testriggens egenskaper. De framtagna krafterna kan då användas i en virtuell fordonsmodell för att se ljud och vibrationsbidragen på fordonsnivå. Källan som har studerats är en slutväxel (rear drive unit) för fyrhjulsdrift i bil. Flera olikametoder för TPA har undersöks, och för karaktärisering av slutväxeln har in-situ metoden valts. Krafter som är oberoende av den mottagande strukturen kallas även ‘blocked forces’. Krafterna beräknas baserat på resultaten från flera olika delmätningar. Validering och även jämförelse medFEM beräkningar har gjorts liksom jämförelser mellan mätningar på enbart komponenten och av hela systemet.
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Granström, Gabriel, and Marie Amann. "Mitigating Not-Invented-Here & Not-Sold-Here Problems : Leveraging External Ideas through Corporate Innovation Hubs." Thesis, Luleå tekniska universitet, Institutionen för ekonomi, teknik och samhälle, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-74354.
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Purpose – The purpose of this study is to understand How Corporate Innovation Hubs (CIHs) can Mitigate NIH and NSH Problems in Knowledge Transfer. To fulfill this purpose, the following research questions were derived: RQ1: What are the causes of NIH & NSH problems among actors collaborating through a CIH? RQ2: What are the consequences of NIH & NSH problems among actors collaborating through a CIH? RQ3: What mechanisms can a CIH use to mitigate NIH & NSH problems among collaborating actors? Method – The study is an explorative inductive multiple case-study, investigating five CIHs situated in either Silicon Valley, US or Gothenburg, Sweden. In total, 39 interviews were conducted in three waves, and results were derived using a Gioia analysis. Findings – This study resulted in a framework illustrating connections of causes and consequences of NIH and NSH problems with corresponding mitigating mechanisms. The most critical causes are Obsessive control (NIH), Internal antagonism (NIH) and Low confidential awareness (NSH). The most severe consequences are Use of irrelevant knowledge (NIH), Suffocation of external ideas (NIH) and Restrained problem-solving (NSH). The most important mitigating mechanisms are Translate relevance of ideas (NIH) and Create mutual confidential understanding (NSH). Theoretical and Practical Implications – This study contributes to the scarce literature on NIH and NSH problems among multiple actors collaborating through CIHs. By identifying causes, consequences and mitigating mechanisms of NIH and NSH problems, CIHs will be able to detect NIH and NSH tendencies among its collaborating actors, to mitigate its causes and prevent its consequences. Limitations and Future Research – The study is limited by the investigated CIHs focus on exploring future transportation solutions, indicating that future studies can investigate CIHs in other industry settings and among other actors collaborating through CIHs. Keywords: Corporate Innovation Hubs; NIH; NSH; Knowledge Transfer
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Nishiyama, Jitsuya. "Confronting Noh Demons: Zeami's Demon Pacifying Noh and Nobumitsu's Demon Killing Noh." PDXScholar, 2019. https://pdxscholar.library.pdx.edu/open_access_etds/5132.
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Noh is often described as a drama of the exploration of the soul. This focus on the human soul is largely attributed to Zeami Motokiyo ä (c. 1363-c. 1443), the greatest playwright in the history of noh drama. This thesis, however, attempts a more comprehensive examination of the characteristics of noh plays by including works by Kanze Nobumitsu (1435-1516). Zeami and Nobumitsu wrote several demon noh plays, which are plays whose primary characters are demons. There are significant differences in characterization and dramaturgy between Zeami's demon noh in the early Muromachi period, the era of noh's founding, and Nobumitsu's onitaiji-mono noh (demon killing noh) in the late Muromachi period, two generations later. In this thesis, I analyze three works by each of those two eminent noh playwrights in order to identify similarities and differences among their works and to compare their styles, structure, theatrical conventions, and use of literary sources. Each of these playwrights represents his era in Japanese literary and political history. By examining socio-cultural aspects of these plays, this thesis will illuminate the changes in Japan's core values over a span of two generations.
Nobumitsu's demon noh plays represent these shifting core values among his patrons who were, like Zeami's, comprised of samurai elites. The social ethos of unification and inclusion in the cultural circle of shogun Ashikaga Yoshimitsu (1358-1408) significantly impacted Zeami's plays. For his patrons like Yoshimitsu, the integration of the aristocratic aesthetics into his plays was essential. Zeami emphasized aristocratic beauty, mysterious gracefulness (yugen), spiritual salvation, and the Zen Buddhist tenets of non-duality, creating complex, humanized demon characters. However, the warrior elite changed significantly in two generations. Nobumitsu's major patrons were powerful warlords during the period when private ambition and revenge prevailed among the samurai and political and military authority was much more fluid than in Zeami's era. For Nobumitsu's patrons, samurai's bravery and resourcefulness were crucial. His waki warrior heroes engage in spectacular combat on stage, fighting and killing powerful, evil demons and kill them. Regional warlords presented these plays to impress their allies, rivals, and their own retainers to expand their prestige in the age of chaos.
New developments in Nobumitsu's noh, make his plays more kabuki-like than Zeami's noh had been. Later forms of theater, kabuki and puppet theater (ningyo joruri) assimilated noh's aesthetics by adapting some noh and kyogen plays throughout its history. Noh drama provided compelling characters and fictional worlds for a variety of plays in kabuki and puppet theater. As early as the mid-Muromachi period, Zeami created humanized demon characters which later playwrights of later genres appropriated for their plays. Nobumitsu created spectacular stage which re-shaped theater and prepared the way for later developments of kabuki and puppet theater in Edo period (1600-1868).