Journal articles: 'Noise-vibration-harshness (NVH)'

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Qatu, M., M. Sirafi, and F. Johns. "Robustness of powertrain mount system for noise, vibration and harshness at idle." Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering 216, no. 10 (October 1, 2002): 805–10. http://dx.doi.org/10.1177/095440700221600103.

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Noise, vibration and harshness (NVH) has become an increasingly important attribute in vehicle engineering. At idle conditions, customer-perceived NVH is dominated by powertrain NVH. Powertrain NVH can be radiated engine noise or noise (and vibration) transmitted through the powertrain mounting system. This paper discusses the variability in the latter NVH as a function of the variability of the mount stiffness parameters. A simple six-degree-of-freedom model is used in the analysis. A detailed design of experiment studies was conducted. It is concluded that better control of mount stiffness parameters would result in improved prediction and performance of idle NVH.

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Ab Aziz, Shamsul Akmar, Risby Mohd Sohaimi, Muhammad Hazwan Pu’ad, and Mohd Abdullah Mohd Yaman. "Noise, Vibration and Harshness (NVH) Study on Malaysian Armed Forces (MAF) Tactical Vehicle." Applied Mechanics and Materials 165 (April 2012): 165–69. http://dx.doi.org/10.4028/www.scientific.net/amm.165.165.

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Noise, Vibration and Harshness (NVH) is the study and modification of the noise and vibration characteristics of vehicles, particularly cars and trucks. NVH parameters which consist of noise (unwanted sound), vibration (mechanical oscillation) and harshness (severity or discomfort of noise or vibration) need to be evaluated in order to improve comfort and safety levels for vehicle occupants. In this paper, NVH study was conducted on Malaysian Armed Forces (MAF) tactical vehicles in order to ensure that the vehicles meet the requirements of the Occupational Safety and Health Administration (OSHA) and Directive 2002/44/EC. The project aim was to identify the preferable solution that can improve the NVH parameters of the vehicles in accordance to the standard and test protocols. A 4x4 Troop Transporter vehicle which carried 8 persons at the rear cabin was used in the NVH testing. The vibration parameters studied are hand arm vibration (HAV), focussing on vibration on the steering wheels of the vehicle, and whole body vibration (WBV), focussing on vibration on the seats. For noise, it was measured at the driver cabin and rear cabin of the vehicles. From the results, the HAV value for driver during idle speed was found to be higher than the others velocity. For WBV, vibration value for passenger 1 in rear cabin was highest compared to the other WBV test points.

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Hua, Xia, Alan Thomas, and Kurt Shultis. "Recent progress in battery electric vehicle noise, vibration, and harshness." Science Progress 104, no. 1 (January 2021): 003685042110052. http://dx.doi.org/10.1177/00368504211005224.

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As battery electric vehicle (BEV) market share grows so must our understanding of the noise, vibration, and harshness (NVH) phenomenon found inside the BEVs which makes this technological revolution possible. Similar to the conventional vehicle having encountered numerous NVH issues until today, BEV has to face many new and tough NVH issues. For example, conventional vehicles are powered by the internal combustion engine (ICE) which is the dominant noise source. The noises from other sources were generally masked by the combustion engine, thus the research focus was on the reduction of combustion engine while less attention was paid to noises from other sources. A BEV does not have ICE, automatic transmission, transfer case, fuel tank, air intake, or exhaust systems. In their place, there is more than enough space to accommodate the electric drive unit and battery pack. BEV is quieter without a combustion engine, however, the research on vehicle NVH is even more significant since the elimination of the combustion engine would expose many noise behaviors of BEV that were previously ignored but would now seem clearly audible and annoying. Researches have recently been conducted on the NVH of BEV mainly emphasis on the reduction of noise induced by powertrain, tire, wind and ancillary system and the improvement of sound quality. This review paper will focus on recent progress in BEV NVH research to advance the BEV systems in the future. It is a review for theoretical, computational, and experimental work conducted by both academia and industry in the past few years.

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Han, Gyu-Been, and Hyung-Seok Kook. "Intake Noise Simulation based on a Noise, Vibration and Harshness Simulator." Transactions of the Korean Society for Noise and Vibration Engineering 30, no. 3 (June 20, 2020): 263–69. http://dx.doi.org/10.5050/ksnve.2020.30.3.263.

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Aziz, Shamsul Akmar Ab, Mohd Zaki Nuawi, Mohd Jailani Mohd Nor, and Dian Darina Indah Daruis. "Study of Noise, Vibration and Harshness (NVH) for Malaysian Army (MA) 3-Tonne Trucks." Applied Mechanics and Materials 471 (December 2013): 74–80. http://dx.doi.org/10.4028/www.scientific.net/amm.471.74.

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Moving vehicle will produce dynamic excitation and can be categorized in the study of noise, vibration and harshness (NVH). Studies of NVH can resolve issues associated with the use of a vehicle comfort. Exposure to some level of noise and vibration can be classified as a danger to vehicle passengers if they are exposed in a standard eight-hour time period. Therefore NVH aspect is the most important aspect in selecting a military vehicle other than the factor of safety, reliability, fuel consumption and maintenance costs. This study was carried out on Malaysian Army (MA) 3-tonne truck drivers who are exposed to noise and vibration produced by the truck. Vibration exposure at seat, steering wheel and body floor was measured using tri-axial and single axis accelerometers which were connected to a Brüel & Kjær Type 3649 vibration analyser, while noise exposure was measured at the drivers ear position using a DuO smart noise monitor. From the results obtained, both vibration and noise pressure levels increased proportionally with the increasing speed of the truck. In the long-term, will have an impact on the health of the truck drivers.

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Kumbhar, S., Subhasis Maji, and Bimlesh Kumar. "Automotive vibration and noise control using smart materials: a state of art and challenges." World Journal of Engineering 10, no. 6 (December 1, 2013): 535–42. http://dx.doi.org/10.1260/1708-5284.10.6.535.

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In the past several years, there has been increased market place awareness of noise, vibration, and harshness performance in automobiles. The differentiation between the quality and reliability levels of automobiles has become less pronounced and, as a result, manufacturers have had to demonstrate superiority by focusing on NVH concerns. The automotive industry is currently spending millions of dollars on NVH work to develop new materials and damping techniques so that the damping treatments are lighter, cheaper, and more effective. Some of the methods used to control noise, vibration, and harshness includes the use of different carpeting treatments, the addition of rubber or asphalt material to car panels, gap sealant, and the injection of expandable foam into body panels. The aim of this study is to explore the feasibility of smart damping materials such as magnet orheological elastomers (MRE), piezoelectric materials, with its basic properties, for augmenting and improving the performance benefits of damping materials. This study also evaluates the noise and vibration benefits of smart damping materials as compared to conventional damping treatments.

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Kumbhar, S., Subhasis Maji, and Bimlesh Kumar. "Automotive vibration and noise control using smart materials: a state of art and challenges." World Journal of Engineering 11, no. 4 (August 1, 2014): 413–20. http://dx.doi.org/10.1260/1708-5284.11.4.413.

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In the past several years, there has been increased market place awareness of noise, vibration, and harshness performance in automobiles. The differentiation between the quality and reliability levels of automobiles has become less pronounced and, as a result, manufacturers have had to demonstrate superiority by focusing on NVH concerns. The automotive industry is currently spending millions of dollars on NVH work to develop new materials and damping techniques so that the damping treatments are lighter, cheaper and more effective. Some of the methods used to control noise, vibration and harshness includes the use of different carpeting treatments, the addition of rubber or asphalt material to car panels, gap sealant, and the injection of expandable foam into body panels. The aim of this study is to explore the feasibility of smart damping materials such as magnetorheological elastomers (MRE), piezoelectric materials, with its basic properties, for augmenting and improving the performance benefits of damping materials. This study also evaluates the noise and vibration benefits of smart damping materials as compared to conventional damping treatments.

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Bang, Tae-Kyoung, Kyung-Hun Shin, Jeong-In Lee, Hoon-Ki Lee, Han-Wook Cho, and Jang-Young Choi. "Experimental and Comparative Study of Rotor Vibrations of Permanent Magnet Machines with Two Different Fractional Pole/Slot Combinations." Applied Sciences 10, no. 24 (December 9, 2020): 8792. http://dx.doi.org/10.3390/app10248792.

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This study deals with the noise, vibration, and harshness (NVH) characteristic analysis of permanent magnet synchronous motors (PMSMs) for electrical machines, such as electrically driven tools that are used in industries. An improved NVH design is needed for application to industrial tools. In general, the electromagnetic NVH characteristics of PMSMs are classified into electromagnetic excitation sources, such as total harmonic distortion of EMF, torque pulsation, magnetic pull force, and unbalanced magnetic force (UMF). This study compares the vibration and noise generated by fractional pole/slot combinations. In PMSMs with fractional pole/slot combinations, UMF is an important NVH source. PMSMs generate UMF because of armature reaction fields based on the pole/slot combinations and harmonics of magnetic flux density. UMF was derived using the finite element method, and the rotor vibration analysis was performed using electromagnetic mechanical coupling analysis. The analysis results and the effect of electromagnetic excitation characteristics on the rotor vibration of the PMSMs were compared and analyzed.

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Hu, Qiao Sheng, Feng Ni, Shu Guang Zuo, Jian Ping Lin, De Guang Fang, and Fu Xiang Guo. "Investigation on Technology of Automobile Vibration and Noise Reduction Based on Body-In-White Structure." Key Engineering Materials 474-476 (April 2011): 676–80. http://dx.doi.org/10.4028/www.scientific.net/kem.474-476.676.

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The automotive body system is not only a source for directly radiating noise into the vehicle interior space, but also a key component for transmitting various vibrations and noise. The optimization of the modes for body-in-white has significant meanings for improving the reliability and NVH (Noise, Vibration and Harshness) performance of the whole vehicle. Based on the current situation that there is more severe interior vibration and noise problem occurring in driving for a light passenger vehicle, a hybrid modal analysis method combined with experiment and simulation methods is applied to investigate the vibration and noise characteristics of the whole vehicle body. By performing such modal analysis, the modal frequencies of the auto-body are improved effectively by strengthening the vibration sensitive regions in the body structure. The experiment for measuring interior vibration and noise levels under cruise condition is conducted to validate that the structural optimization for body-in-white has significant contribution for improving the whole vehicle NVH performance.

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Plättner, David. "E-Kompressoren entkoppeln." Lärmbekämpfung 16, no. 05 (2021): 154–55. http://dx.doi.org/10.37544/1863-4672-2021-05-24.

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Vibracoustic, ein weltweit führender Anbieter von NVH-Lösungen (Noise, Vibration and Harshness) für die Automobilindustrie, hat ein innovatives neues Entkopplungssystem für elektrische Kompressoren in modernen Elektrofahrzeugen und Plug-in-Hybrid- Fahrzeugen auf den Markt gebracht. Die neue Lösung adressiert viele der NVH-Herausforderungen, mit denen Fahrzeughersteller konfrontiert sind, wenn es darum geht, das Wärmemanagement der Batterien zu optimieren und gleichzeitig übermäßige Geräusche und Vibrationen von extrem beanspruchten E-Kompressoren auszugleichen.

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Han, Su, Yiqi Zhou, Yanzhao Chen, Chenglong Wei, Rui Li, and Bo Zhu. "Ontology-Based Noise Source Identification and Key Feature Selection: A Case Study on Tractor Cab." Shock and Vibration 2019 (February 3, 2019): 1–14. http://dx.doi.org/10.1155/2019/6572740.

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This paper proposes an ontology-based noise source identification method, establishes an ontology knowledge expression model in the field of noise, vibration, and harshness (NVH), and provides an extensible framework for sharing noise diagnosis knowledge in the field. Based on the key features extracted from the noise and vibration signals at different positions and the prior knowledge, mechanical engineers can construct an ontology rule and locate noise sources by identifying the intrinsic relationship between signal characteristics through ontology reasoning. A case study is conducted to demonstrate the effectiveness of the proposed method in resolving the problem of integrating multisource heterogeneous knowledge and exchanging noise diagnosis knowledge information in the field of NVH for agricultural machines. Thus, our study facilitates the sharing and reuse of knowledge and advances the development of intelligent noise diagnosis expert systems to a certain extent.

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Bischof, Wolfgang, Florian Draeger, Martin Hennen, and Ralph Kennel. "Operating Point Adaptation for NVH-Optimization of Induction Machines." World Electric Vehicle Journal 9, no. 1 (June 7, 2018): 10. http://dx.doi.org/10.3390/wevj9010010.

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Inverter-fed drive systems are mostly optimized to operate at the best efficiency, neglecting the possibility of acoustic optimization. The chosen operating point can lead to undesired harmonics involving vibrations and noises of the electrical drive. In order to optimize the system with respect to acoustics, the given operating point for best efficiency is left and a noise, vibration and harshness (NVH)-optimized operating point is chosen. This paper shows the influence of the operating point on NVH, describes an NVH-optimized control and draws a comparison between simulation and measurement.

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Jung, H. S., S. H. Lee, H. S. Woo, M. S. Kim, H. H. Park, and B. K. Min. "Advancement of Noise, Vibration and Harshness (NVH) Performance of Vehicle Rubber Hoses." Asian Journal of Chemistry 25, no. 8 (2013): 5215–20. http://dx.doi.org/10.14233/ajchem.2013.f21.

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Kropp, Andreas, and Daniel Heiserer. "Efficient Broadband Vibro-Acoustic Analysis of Passenger Car Bodies Using an FE-Based Component Mode Synthesis Approach." Journal of Computational Acoustics 11, no. 02 (June 2003): 139–57. http://dx.doi.org/10.1142/s0218396x03001870.

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The costliest part of computationally optimizing automobiles for Noise, Vibration and Harshness (NVH) is the frequency response calculation of very large finite element models. In general, NVH is treated as a fluid-structure interaction between the body and the car interior fluid volume. In this paper, some features of the current approach to NVH computations at BMW are elucidated. First, the equations of motion for a typical NVH problem will be derived using three different formulations, differential, algebraic and modal. Next, three numerical approaches for solving the large systems of equations (direct, modal and Automated Multi-Level Substructuring (AMLS)) will be shown. Finally, the numerical precision and the efficiency of these approaches will be assessed.

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Kaal, William, and Sebastian Rieß. "Hochfrequente Charakterisierung und Modellierung von Elastomerlagern." Konstruktion 71, no. 05 (2019): 62–65. http://dx.doi.org/10.37544/0720-5953-2019-05-62.

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Im Auslegungsprozess neuer Fahrzeuge wird dem NVH-Verhalten des Fahrwerks eine immer stärkere Rolle beigemessen, wobei unter NVH (Noise, Vibration, Harshness) die Gesamtheit der spür- und hörbaren Schwingungen verstanden wird. Elastomerkomponenten im Fahrwerksbereich werden daher nicht nur hinsichtlich ihrer niederfrequenten Dynamik zur Abbildung komplexer Elastokinematiken ausgelegt, sondern auch hinsichtlich ihrer akustischen Eigenschaften. Aus diesem Grund ist eine detaillierte Kenntnis ihres hochdynamischen Verhaltens essentiell. Am Fraunhofer-Institut LBF in Darmstadt werden daher Elastomerlager hochfrequent charakterisiert und multiaxiale numerische Modelle abgeleitet, die eine schnelle und effiziente Gesamtsystemsimulation auf Fahrzeugebene ermöglichen.

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Ni, E.-J., D. S. Snyder, G. F. Walton, N. E. Mallard, G. E. Barron, J. T. Browell, and B. N. Aljundi. "Radiated Noise from Tire/Wheel Vibration." Tire Science and Technology 25, no. 1 (January 1, 1997): 29–42. http://dx.doi.org/10.2346/1.2137528.

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Abstract As a general trend, vehicle sound quality has significantly improved in recent years. This is primarily due to improved body structure and powertrain design. As demand for better vehicle sound quality increases, it is important to study all possible noise sources contributing to noise, vibration, and harshness (NVH). Tire vibration has long been recognized as a source of airborne noise. Some effects of wheel design on tire noise have also been well understood for sometime. But the dynamic interaction between tire and wheel designs and its effect on vehicle NVH, although frequently observed for many years, has only recently been identified in the 200–350 Hz frequency range. Different wheels can produce perceptible differences in vehicle interior sound pressure levels in a road test. Hence, the authors have developed a process to quantify and reduce noise caused by a vibrating tire/wheel assembly. This paper discusses the general flow of the process, which begins with the identification of NVH issues on a total vehicle level. Modeling and optimization of the aluminum wheel was chosen as the focus of this project for two reasons. First, the interior sound pressure level (SPL) around 285 Hz is about 5–7 dBA higher in a vehicle equipped with aluminum wheels rather than a steel design. Second, modifying the wheel is far more economical and faster due to its simplicity of design than the complexity of either the vehicle body structure or a tire.

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Yu, Zhenqi, Dong Cheng, and Xingyuan Huang. "Low-Frequency Road Noise of Electric Vehicles Based on Measured Road Surface Morphology." World Electric Vehicle Journal 10, no. 2 (May 30, 2019): 33. http://dx.doi.org/10.3390/wevj10020033.

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In this paper, the noise vibration harshness (NVH) road surface morphology of a test site is scanned to establish a data processing system for the road surface, which can be used to transform the road surface morphology into the road surface excitation required for the road noise simulation analysis. The road surface morphology of the test site is used as the excitation input of the simulation analysis. The results obtained from the simulation analysis are equivalent to the experimental results. Using the actual scanning road surface morphology to simulate the excitation of a vehicle, the noise, as well as the vibration response of the vehicle under the actual road excitation of NVH in the early stage of vehicle development, can be accurately predicted. In the physical prototype stage, the rectification of vehicle road noise and the optimization to provide the needed excitation for the simulation analysis can be done, which will reduce the labor costs of the relevant experiment. Therefore, this method of road noise research has important engineering significance.

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Úradníček, Juraj, Pavel Kraus, Miloš Musil, and Michal Bachratý. "Investigation of Frictional Stick-Slick Effect in Disk Brake NVH." Strojnícky casopis – Journal of Mechanical Engineering 67, no. 1 (April 1, 2017): 93–100. http://dx.doi.org/10.1515/scjme-2017-0010.

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Abstract Paper describes the mechanism of vibration of a minimal automotive disc brake model which can lead to unwanted effects known as brake Noise Vibrations and Harshness (NVH). Stick-slip frictional effects are mathematically described by simplification of physical assumptions. Self-excited vibrations due to stick-slip and also stability conditions are defined using a 1 degree of freedom mechanical system. Non-Coulomb nonlinear behavior of the friction force with negative slope is considered. Response is obtained by the numerical solution of ordinary differential equation.

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Wang, Yongchao, Hui Gao, Haiyang Wang, and Wenpeng Ma. "NVH Optimization Analysis of Permanent Magnet Synchronous Motor by Rotor Slotting." Vehicles 2, no. 2 (May 20, 2020): 287–302. http://dx.doi.org/10.3390/vehicles2020016.

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With the development of new energy vehicles, the NVH (Noise, Vibration, Harshness) performance of the permanent magnet synchronous motors (PMSM) for vehicles has attracted more and more attention. The rotor slotting optimization analysis is the critical issue in the NVH performance study of PMSM. In this paper, the theoretical formula of the PMSM radial electromagnetic force is presented. Based on which, the spatial order and frequency order characteristics of the radial force of a 6-pole 36-slot PMSM are analyzed. Firstly, electromagnetic simulation of the motor is carried out, and the specific force components, which may cause an NVH problem, is extracted. Secondly, the harmonics are calculated with a method of freezing the relative magnetic permeability. Thirdly, the motor is optimized by rotor slotting to reduce the amplitudes of these harmonics, and the effect on electromagnetic noise is analyzed in theory and simulation. Finally, the NVH test in original state and after rotor slotting state was performed in the semi-anechoic chamber. The accuracy of the theory and simulation was verified based on the comparison of the measured noise data. This paper provides a new NVH optimization idea, this method can quickly locate the fundamental problem location of electromagnetic NVH, provide a fast channel for electromagnetic NVH optimization from simulation to verification, and improve the optimization efficiency of NVH.

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Raichel, Daniel R. "Noise, vibration and harshness (NVH) criteria as functions of vehicle design and consumer expectations." Journal of the Acoustical Society of America 118, no. 3 (September 2005): 1887. http://dx.doi.org/10.1121/1.4779565.

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Sobieszczanski-Sobieski, J., S. Kodiyalam, and R. Y. Yang. "Optimization of car body under constraints of noise, vibration, and harshness (NVH), and crash." Structural and Multidisciplinary Optimization 22, no. 4 (November 1, 2001): 295–306. http://dx.doi.org/10.1007/s00158-001-0150-6.

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Noorazizi, M. S., B. A. Aminudin, and M. I. Zetty. "Systematic Fea Study of Vehicle Exhaust System Hanger Location Using Addofd Method." Applied Mechanics and Materials 392 (September 2013): 161–64. http://dx.doi.org/10.4028/www.scientific.net/amm.392.161.

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Under excitation of the engine and road surface, the vibration energy of the exhaust system which will result in the vibration of the body and produce the structure noise transfers to the body from the hanger. In view of these problems will cause noise, vibration and harshness (NVH) performance of the vehicle. A method called averaged driving DOF displacement (ADDOFD) is used to determine and optimize the exhaust hanger locations in this paper. Based on a sample vehicle, the Hyper Mesh and MSC. Nastrans oftware are adopted for meshing and calculation in the FEM modeling and vibration modal analysis of the exhaust system. Exhaust systems free-free mode and sum of its eigenvectors are offered using MSC. Nastran. Hanger locations are recommended at the position where the ADDOFD is relatively lower. Then static analysis and dynamic analysis of the exhaust system are done, and finally hanger locations of the exhaust system are selected. When the reasonable hanger positions have been decided, the vibration level of the body and the internal noise would have been decreased. This method can effectively select better NVH performance hanger locations in the earlier vehicle development process and can be extended to other types of vehicle, thus is instructive for saving both the time and the cost of operation.

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Treszkai, Marcell Ferenc, and Dániel Feszty. "Review of Hybrid Finite Element – Statistical Energy Analysis methods in vehicle NVH predictions." Acta Technica Jaurinensis 12, no. 4 (November 27, 2019): 347–70. http://dx.doi.org/10.14513/actatechjaur.v12.n4.513.

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In the vehicle industry, the noise, vibration and harshness (NVH) characteristics of a car are becoming more and more important. In order to control these, it is necessary to know the sources and contributors to the interior noise level. This paper provide an overview of the state-of-the-art on predicting the NVH characteristics of fully trimmed vehicles in the mid-frequency gap between 400 Hz to 1 kHz. It is shown that for this frequency range, typically a hybrid FE-SEA method is used. This method provides a mixture of the advantages of the deterministic and statistical approaches. The first part of the paper introduces the method, followed by an overview of the different fields of usage in the vehicle industry. At the end of the paper, gaps in the knowledge are identified.

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Prokop, Aleš, Kamil Řehák, Martin Zubík, and Pavel Novotný. "Experimental Validation Of The Gearbox NVH Parameters." Journal of Middle European Construction and Design of Cars 13, no. 2 (November 1, 2015): 16–21. http://dx.doi.org/10.1515/mecdc-2015-0007.

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Abstract The noise, vibration and harshness (NVH) plays an important role in the transmission area of automotive industry. To understand all the impacts on the gearbox’s global dynamic behavior it is necessary to gain information from a simplified model, create methods and get an appropriate and well correlated results with the experiment. The method itself can be afterwards reused for more complex transmission, which could be supported by other measurements. This paper deals with creation of a gearbox’s simplified model, including essential mechanisms as gear mesh stiffness, backlash, bearing stiffness and modal properties of the main components. Except for the presented model, more models with different difficulty levels are used. Numerical results are compared with data from experiment with good correlation.

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Minas, I., N. Morris, S. Theodossiades, M. O’Mahony, and J. Voveris. "Automotive dry clutch fully coupled transient tribodynamics." Nonlinear Dynamics 105, no. 2 (July 2021): 1213–35. http://dx.doi.org/10.1007/s11071-021-06605-x.

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AbstractDetermining the root causes of Noise, Vibration and Harshness (NVH) phenomena in modern automotive drivetrains is a task of critical importance. This research investigates the stability of dry clutch systems vibrational behaviour during engagement. A fully coupled dry clutch numerical model including the influence of friction is presented and validated using vehicle measurements. The clutch component frictional properties are measured using parts that exhibit aggressive NVH behaviour using representative tribometric experiments. The validated numerical tool highlights the occurrence of instabilities which are caused by modal couplings, particularly between the input shaft bending and clutch disc radial motions. Such a validated transient dynamics model of a dry clutch system has not hitherto been presented in the open literature.

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Zheng, Xu, Xuan Luo, Yi Qiu, and Zhiyong Hao. "Modeling and NVH Analysis of a Full Engine Dynamic Model with Valve Train System." Applied Sciences 10, no. 15 (July 27, 2020): 5145. http://dx.doi.org/10.3390/app10155145.

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The valve train system is an important source of vibration and noise in an engine. An in-depth study on the dynamic model of the valve train is helpful in understanding the dynamic characteristics of the valve train and improving the prediction accuracy of vibration and noise. In the traditional approaches of the dynamic analyses, the simulations of the valve train system and the engine are carried out separately. The disadvantages of these uncoupled approaches are that the impact of the cylinder head deformation to the valve train and the support and constraints of the valve train on the cylinder head are not taken into consideration. In this study, a full engine dynamic model coupled with a valve train system is established and a dynamic simulation and noise vibration harshness (NVH) analysis are carried out. In the coupled approach, the valve train system is simulated simultaneously with the engine, and the complexity of the model has been greatly increased. Compared with the uncoupled approach, more detailed dynamic results of the valve train can be presented, and the subsequent predictions of vibration and noise can also be more accurate. The acoustic results show that the difference from the experimental sound power level is reduced from 1.8 dB(A) to 0.9 dB(A) after applying the coupled approach.

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Noorazizi, M. S., B. A. Aminudin, and H. Faraziah. "Technique for Hanger Location of Vehicle Exhaust System Using Finite Element Method." Applied Mechanics and Materials 663 (October 2014): 485–89. http://dx.doi.org/10.4028/www.scientific.net/amm.663.485.

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A simulation technique using a finite element method (FEM) model for predicting, reducing and optimizing vibrations of the exhaust system was developed in this paper. This paper postulates the first stage in the design analysis of an exhaust system. Under excitation of the engine and road surface, the vibration energy of the exhaust system will result in the vibration of the body and produce structure noise transfers to the body from the hanger. These problems will effect or compromise noise, vibration and harshness (NVH) performance of the vehicle. A method called averaged driving DOF displacement (ADDOFD) is used to determine and optimize the exhaust hanger locations in this paper. Based on a sample vehicle, the HyperMesh and MSC Nastran software are adopted for meshing and calculation in the FEM modeling and vibration modal analysis of the exhaust system. Exhaust system’s free-free mode and sum of its eigenvectors are solved using MSC Nastran. Hanger locations are recommended at the position where the ADDOFD is relatively lower. Then static analysis and dynamic analysis of the exhaust system are performed, and finally hanger locations of the exhaust system are selected. When reasonable hanger positions have been decided, the vibration level of the body and the internal noise would have been decreased. This method can effectively select better NVH performance hanger locations in the earlier vehicle development process and can be extended to other types of vehicle, thus is effective for saving both the time and the cost of operation.

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Juang, T. B., M. Cheng, and L. Na. "Experimental and finite element analyses of a sliding-tube-type driveshaft-induced vehicle vibration." Proceedings of the Institution of Mechanical Engineers, Part K: Journal of Multi-body Dynamics 221, no. 3 (September 1, 2007): 375–85. http://dx.doi.org/10.1243/14644193jmbd76.

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Driveline noise, vibration, and harshness (NVH) has become an integral attribute in defining how the vehicle NVH performance is perceived by the customers of the automotive industry. The driveshaft component design requirements need to make sure that the designed driveline system is robust and reliable in order to achieve the vehicle NVH targets. They also need to ensure that the system maintains its durability performance as well. A slip mechanism in the driveline system is needed to accommodate the movements caused by the rear axle and rear suspensions when the vehicle travels on a rough road or accelerates/ decelerates abruptly. One design option to accommodate the slip mechanism is to use a press-fitted sliding-tube design. This slip mechanism causes the fluctuation of the contact forces in the tubes, particularly in the vehicle coast down course, and becomes a non-linear contact force phenomenon. This paper uses experimental and finite element method linear tools to explain the non-linear behaviour of the sliding-tube driveshaft, and to provide design options to prevent vehicle vibration issues created by the current sliding-tube driveshaft design.

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Guo, Han, Jianwu Zhang, and Haisheng Yu. "Robust optimisation of dynamic and NVH characteristics for compound power-split hybrid transmission." Proceedings of the Institution of Mechanical Engineers, Part K: Journal of Multi-body Dynamics 233, no. 4 (June 25, 2019): 817–26. http://dx.doi.org/10.1177/1464419319856774.

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In this paper, vibro-acoustic characteristics of a power-split hybrid transmission including a compound planetary gear set are investigated by numerical procedure and refined system dynamics modelling. For validation of the numerical predictions, bench tests are performed for dynamic and acoustic responses of the hybrid transmission, contribution rates of acoustic radiation power induced due to the planetary gears, support bearings, transmission shafts and the gearbox housing are estimated. In improving the noise, vibration and harshness (NVH) performance of the transmission during hybrid vehicle acceleration, traction torques of the motors against the planetary gear parametric resonance are formulated and an optimal control strategy is proposed. By real road NVH test results acquired on board of the midsize hybrid car, it is demonstrated that a significant reduction of the planetary gear whine noise is achieved. As a result, numerical approaches applied to establish relationships between torques of the two traction motors and parametric excitations of the compound planetary gear train are experimentally validated.

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Wu, Xudong, Minghai Zhang, Shuguang Zuo, Haidong Huang, and Hao Wu. "An investigation on interior noise reduction using 2D locally resonant phononic crystal with point defect on car ceiling." Journal of Vibration and Control 25, no. 2 (June 20, 2018): 386–96. http://dx.doi.org/10.1177/1077546318782242.

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Interior noise, as one of the indicators of automotive NVH (noise, vibration and harshness) performance, has been associated with an increasing importance in ride comfort evaluation. This paper presents a new method of interior noise reduction based on phononic crystal theory. Considering the lightweight requirement, the car ceiling plate is divided into nine regions to determine where the phononic oscillators should be mounted. By leveraging the acoustic contribution analysis of each region, the phononic crystal is arranged in the region that contributes the most to interior noise, bringing out the best attenuation effect in its bandgap. However, it is noted that at certain frequencies, the vibration of the ceiling plate or other body plates, which exhibits negative contribution to interior noise, should not be attenuated due to their beneficial effects. Thus in this paper, a point defect is employed for the design of a two-dimensional (2D) phononic crystal structure to preserve the negative contribution part of the plate’s vibration at specific frequencies. The validity of the proposed method in interior noise reduction is verified by simulation. Moreover, the error analysis is implemented and an optimization scheme is proposed.

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von Wysocki, Timo, Michael Leupolz, and Frank Gauterin. "Metamodels Resulting from Two Different Geometry Morphing Approaches Are Suitable to Direct the Modification of Structure-Born Noise Transfer in the Digital Design Phase." Applied System Innovation 3, no. 4 (November 6, 2020): 47. http://dx.doi.org/10.3390/asi3040047.

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Noise vibration and harshness (NVH) development often takes place in the later development phases. Shifting the optimization to the early digital development phase enables more parameters to participate in the optimization and leads to a more holistic development process. Digital NVH development often modifies system and component frequency response functions (FRFs) using finite element (FE) simulation. Currently, the often manual process of creating new FE models for modified designs makes a systematic evaluation of many designs difficult and time-consuming. In this paper, we take on these difficulties and use both a Direct Morphing approach and a Box Morphing approach to automatically adopt the first existing FE models to modified designs. We use the generated simulation results to fit metamodels describing the correlation between geometrical parameters and characteristic FRF values. These metamodels provide an easy and fast to use tool for designers to consider NVH demands. In a simulation example, we demonstrate the capabilities by modifying the kinematic hard points of a vehicle suspension and using them to modify the noise transfer sensitivity. We show that the metamodels can lead the digital design process to intuitively and specifically reduce characteristic component FRF values by changing the location of the component hard points.

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Farshidianfar, A., M. Ebrahimi, H. Rahnejat, M. T. Menday, and M. Moavenian. "Optimization of the high-frequency torsional vibration of vehicle driveline systems using genetic algorithms." Proceedings of the Institution of Mechanical Engineers, Part K: Journal of Multi-body Dynamics 216, no. 3 (September 1, 2002): 249–62. http://dx.doi.org/10.1177/146441930221600305.

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Vehicle drivelines with manual transmissions are exposed to different dynamic engine torques under driving conditions. Engine torque can dramatically vary with throttle demand from coast to drive condition and, conversely, with throttle release from drive to coast. Abrupt application or release of throttle in slow moving traffic or rapid engagement of the clutch can be followed by an audible response, referred to in industry as the clonk noise. This paper presents a complete dynamic model of a vehicle driveline for the optimization of high-frequency torsional vibration by the distributed-lumped (hybrid) modelling technique (DLMT). The model used is first validated against experimental tests. Parameter sensitivity studies have been carried out using the model to identify the important components affecting clonk. Three key parameters have been chosen from the parameter study. To optimize these key factors, genetic algorithms (GAs) have been used in this multi-parameter optimization problem. The GAs show significant reduction in the driveline noise, vibration and harshness (NVH).

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Yu, Wentao. "Analysis and Optimization of Low-Speed Road Noise in Electric Vehicles." Wireless Communications and Mobile Computing 2021 (May 8, 2021): 1–15. http://dx.doi.org/10.1155/2021/5537704.

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When a certain electric vehicle is driving at a constant speed of 40 km/h on the rough asphalt road, the rear passenger can obviously feel the ear pressure, which seriously affects the comfort. Through the analysis of objective data, it was found that the problem was caused by the road excitation, which leads to the coupling between the mode of the backup door and the mode of the acoustic cavity, and causes the resonance of the car cavity, thus causing the ear pressure sensation. To solve this problem, this paper optimizes the backup door by means of experiment and simulation, increases the dynamic vibration absorber, makes its modal frequency avoid the acoustic cavity modal frequency, and achieves the purpose of reducing the interior noise. After optimization, the vehicle noise is reduced by 8 dBA at 42 Hz under 40 km/h working condition of rough road surface, and the ear pressure sensation is reduced at the same time, thus improving the NVH (noise, vibration, and harshness) performance of the vehicle.

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Aladdin, M. F., N. A. A. Jalil, N. Y. Guan, K. A. M. Rezali, and S. A. Adam. "Evaluation of Human Discomfort from Combined Noise and Whole-Body Vibration in Passenger Vehicle." International Journal of Automotive and Mechanical Engineering 16, no. 2 (July 5, 2019): 6808–24. http://dx.doi.org/10.15282/ijame.16.2.2019.25.0512.

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Exposure to noise and whole-body vibration (WBV) has been a key element in determining comfort levels in transportation systems. In the automotive industry, researchers and engineers continuously work on reducing noise and vibration levels to minimize discomfort. Noise annoyance in vehicles results from structure-borne as well as air-borne noise from vehicle powertrain, tires and aeroacoustics. Whole-body vibration affects vehicle passenger comfort at the seat pan, back rest and feet. The objective of this research is to evaluate the comfort level of seated passengers in a vehicle from noise and whole-body vibration by considering both separate and combined modality. The noise and vibration data were recorded and analysed in two vehicles on the same highway road with four different speeds. The vibration exposure in vehicle were evaluated based on ISO2631-1:1997. Noise exposure was based on A-weighted sound pressure level. The combined discomfort on noise and vibration were quantified. The vibration results identified clear dominant of z-axis vertical vibration on seat pan, backrest and feet in both vehicles. The discomfort of combined noise and vibration showed that vehicle B caused a higher discomfort level at the high vehicle speed of 90 km/h and 110 km/h. The Relative Discomfort Indicator (RDI) were introduced to compare levels of discomfort from noise and vibration in different vehicles with varying speeds. The result suggests that the RDI value for vehicle A relative to vehicle B is negative at higher vehicle speed which further indicates that at higher speed, vehicle B have a higher discomfort level compared to vehicle A. The RDI value is expected to be useful for automotive Noise, vibration and harshness (NVH) improvement.

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Senthil Kumar, M., C. D. Naiju, S. J. Chethan Kumar, and Joseph Kurian. "Vibration Analysis and Improvement of a Vehicle Chassis Structure." Applied Mechanics and Materials 372 (August 2013): 528–32. http://dx.doi.org/10.4028/www.scientific.net/amm.372.528.

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Product development cycle time is very important in automotive industry which is very competitive nowerdays. New products are introduced into the market with better designs in short period of time by carrying out different engineering analysis. This study is focused on analyzing the existing chassis design and the noise, vibration and harshness(NVH) characteristics are studied. Modeling of chassis structure is carried out using 3D modelling package CATIA V5 and finite element model is created by meshing using Hypermesh software. The main objective is to find the natural frequency and analyse the mode shape of the automotive chassis structure. Results of the analysis will help to study the dynamic behavior of the chassis structure with load application/real road condition and to improvise the car chassis structure assembly.

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Gioia, Nicoletta, Cédric Peeters, Patrick Guillaume, and Jan Helsen. "Identification of Noise, Vibration and Harshness Behavior of Wind Turbine Drivetrain under Different Operating Conditions." Energies 12, no. 17 (September 3, 2019): 3401. http://dx.doi.org/10.3390/en12173401.

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Noise, vibration and harshness (NVH) problems are critical issues to be tackled for wind turbine drivetrains. Tracking the behavior of modal parameters of the machines’ fundamental modes during operation it is of high interest to validate complex simulation models. A powerful approach for this purpose is represented by operational modal analysis (OMA). This paper describes the investigation of an automated technique for continuously tracking the modes of a rotating mechanical system running in normal operating conditions. The modal estimation procedure is based on an automatic version of the pLSCF (poly-reference Least-Square Complex Frequency-Domain) algorithm. The latter is coupled with a method that automatically tracks the modal parameters along different data sets. The use of OMA on a rotating component of the wind turbine creates the need to deal with harmonics in order to satisfy one of the assumptions of OMA. For this purpose, the use of a cepstrum editing procedure is analyzed and implemented. Modal estimates obtained from an automated analysis on stand still data and normal operating conditions data are compared, to test the added value of the cepstrum editing procedure and the robustness of the method when used on real data. To illustrate and validate the implemented methodology, data acquired during a long-term monitoring campaign of a wind turbine drivetrain are used.

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37

Lazzari, Alessandro, Davide Tonazzi, Giovanni Conidi, Cristian Malmassari, Andrea Cerutti, and Francesco Massi. "Experimental Evaluation of Brake Pad Material Propensity to Stick-Slip and Groan Noise Emission." Lubricants 6, no. 4 (December 11, 2018): 107. http://dx.doi.org/10.3390/lubricants6040107.

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Frictional and dynamic responses of brake pad materials, when sliding on brake disc counterfaces, are at the origin of noise, vibration and harshness (NVH) issues such as brake noise emissions. In more detail, groan is a low frequency noise emission often associated to the stick-slip frictional response of the brake system. The instability of such contact is the result of the coupling between the system dynamics and the frictional response of the materials in contact. In this work, an experimental approach is proposed for measuring the frictional response and the propensity to generate stick-slip of different lining materials, coming from commercial brake pads, when sliding on a worn surface of a brake disc, under the same controlled boundary conditions. The proposed methodology allowed for comparing the propensity of the tested pad materials to stick-slip vibrations, which is in agreement with feedback from automotive industry on groan emission.

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38

Dong, Jun, Kyung K. Choi, and Nam H. Kim. "Design Optimization for Structural-Acoustic Problems Using FEA-BEA With Adjoint Variable Method." Journal of Mechanical Design 126, no. 3 (October 1, 2003): 527–33. http://dx.doi.org/10.1115/1.1701879.

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A noise-vibration-harshness (NVH) design optimization of a complex vehicle structure is presented using finite element and boundary element analyses. The steady-state dynamic behavior of the vehicle is calculated from the frequency response finite element analysis, while the sound pressure level within the acoustic cavity is calculated from the boundary element analysis. A reverse solution process is employed for the design sensitivity calculation using the adjoint variable method. The adjoint load is obtained from the acoustic boundary element re-analysis, while the adjoint solution is calculated from the structural dynamic re-analysis. The evaluation of pressure sensitivity only involves a numerical integration process over the structural part where the design variable is defined. A design optimization problem is formulated and solved, where the structural weight is reduced while the noise level in the passenger compartment is lowered.

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Zhong, Biqing, Bin Deng, and Han Zhao. "Simulation Model and Method for Active Torsional Vibration Control of an HEV." Applied Sciences 9, no. 1 (December 22, 2018): 34. http://dx.doi.org/10.3390/app9010034.

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Hybrid electric vehicles (HEV) might cause new noise vibration and harshness (NVH) problems, due to their complex powertrain systems. Therefore, in this paper, a new longitudinal dynamic simulation model of a series-parallel hybrid electric bus with an active torsional vibration control module is proposed. First, the schematic diagrams of the simulation model architecture and the active control strategy are given, and the dynamic models of the main components are introduced. Second, taking advantage of the characteristics of hybrid systems, a method of determining the key dynamic parameters by a bench test is proposed. Finally, in a typical bus-driving cycle for Chinese urban conditions, time domain and frequency domain processing methods are used to analyze vehicle body jerk, fluctuation of rotational speed, and torsional angle of the key components. The results show that the active control method can greatly improve the system’s torsional vibration performance when switching modes and at resonance.

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40

Longana, Marco, Vaclav Ondra, HaNa Yu, Kevin Potter, and Ian Hamerton. "Reclaimed Carbon and Flax Fibre Composites: Manufacturing and Mechanical Properties." Recycling 3, no. 4 (November 22, 2018): 52. http://dx.doi.org/10.3390/recycling3040052.

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The feasibility of using the HiPerDiF (high performance discontinuous fibre) method to manufacture highly aligned discontinuous fibres intermingled hybrid composites with flax and reclaimed carbon fibres (rCF), and the potential benefits of so doing, are investigated in this paper. It is demonstrated that, despite their hydrophilic nature, flax fibres are not affected by this water-based process. Intermingled flax/rCF hybrid composites are characterised in terms of their tensile and vibrational response. It is concluded that natural/rCF fibre hybrid composites can be a viable solution for those applications where a reduction in primary mechanical properties, e.g., stiffness and strength, is an acceptable trade-off for the enhancement of secondary properties, e.g., noise, vibration, and harshness (NVH) mitigation, and the reduction of monetary costs.

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Yung, V. Y. B., and D. J. Cole. "Wavelet analysis of high-frequency damper behaviour." Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering 219, no. 8 (August 1, 2005): 977–88. http://dx.doi.org/10.1243/095440705x11248.

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This paper describes research into the performance of a hydraulic automotive damper at frequencies up to 500 Hz. A review of published literature found little information on damper behaviour above 30 Hz. Design of vehicles for low levels of noise, vibration, and harshness (NVH) requires attention to these higher frequencies. The high-frequency force-velocity behaviour of a monotube damper was measured. Excitations included two-frequency inputs and a random input. In addition to traditional data analysis methods, techniques based on the wavelet transform were used. The results indicate that friction and hydraulic valve flow at near-zero velocity are important mechanisms in determining high-frequency force generation. Another significant mechanism is the transition between notch (leakage) flow and disc valve flow.

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Tang, Zhaoping, Min Wang, Xiaoying Xiong, Manyu Wang, Jianping Sun, and Li Yan. "Optimal design of noise reduction and shape modification for traction gears of EMU based on improved BP neural network." Noise Control Engineering Journal 69, no. 4 (July 1, 2021): 373–88. http://dx.doi.org/10.3397/1/376934.

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Under high-speed operating conditions, the noise caused by the vibration of the traction gear transmission system of the Electric Multiple Units (EMU) will distinctly reduce the comfort of passengers. Therefore, analyzing the dynamic characteristics of traction gears and reducing noise from the root cause through comprehensive modification of gear pairs have become a hot research topic. Taking the G301 traction gear transmission system of the CRH380A high-speed EMU as the research object and then using Romax software to establish a parametric modification model of the gear transmission system, through dynamics, modal and Noise Vibration Harshness (NVH) simulation analysis, the law of howling noise of gear pair changes with modification parameters is studied. In the small sample training environment, the noise prediction model is constructed based on the priority weighted Back Propagation (BP) neural network of small noise samples. Taking the minimum noise of high-speed EMU traction gear transmission as the optimization goal, the simulated annealing (SA) algorithm is introduced to solve the model, and the optimal combination of modification parameters and noise data is obtained. The results show that the prediction accuracy of the prediction model is as high as 98.9%, and it can realize noise prediction under any combination of modification parameters. The optimal modification parameter combination obtained by solving the model through the SA algorithm is imported into the traction gear transmission system model. The vibration acceleration level obtained by the simulation is 89.647 dB, and the amplitude of the vibration acceleration level is reduced by 25%. It is verified that this modification optimization design can effectively reduce the gear transmission.

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43

Zhang, Fan, Ke Chen, Desmond Appiah, Bo Hu, Shouqi Yuan, and Stephen Ntiri Asomani. "Numerical Delineation of 3D Unsteady Flow Fields in Side Channel Pumps for Engineering Processes." Energies 12, no. 7 (April 3, 2019): 1287. http://dx.doi.org/10.3390/en12071287.

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Side channel pumps are important machines for handling toxic, explosive or other dangerous liquids in various engineering processes. However, the operational reliability of these pumps is directly affected by the intensity of the pressure and velocity fluctuations, thus the flow fluctuations existing within the pump cannot be neglected because of their direct influence on the noise, vibration and harshness performance. Therefore, describing precisely the zones of highly unsteady and turbulent flow fields is a key research topic. Moreover, the size of the wrapping angle strongly affects the levels of pressure and velocity fluctuations, thus numerical calculations of the pressure and velocity fluctuation intensities in side channel pump models with different wrapping angles were conducted in this work. The results indicated that the pressure fluctuation coefficient increased gradually from the inflow to the outflow. At the interrupter, the flow experienced the most irregular flow patterns in the pump. The flow at the inflow region in both the impeller and side channel passage rendered weak pressure fluctuation intensities. All three pump cases operated with 24 blades but after one complete circulatory cycle, cases 1, 2 and 3 revealed 21, 20 and 19 regular pressure fluctuations respectively in the impeller flow passage. On the other hand, the side channel flow passage rather produced 24 regular pressure fluctuations. Furthermore, the main frequency harmonic excitations for all studied monitoring points in the impeller and side channel flow passages of the three pump cases occurred at 600 Hz (24 × fn), 1200 Hz (48 × fn), and 1800 Hz (72 × fn). For this reason, exchanged flow times between the impeller and side channel is mainly responsible for the pressure fluctuation which subsequently affects the noise and vibration generation in the side channel pump. Hence, the results could be used as a reference for Noise-Vibration-Harshness (NVH) study in turbomachinery especially modifying the side channel pump in order to improve the operational reliabilities for many engineering processes.

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Liu, Jie, Ling Tong, Chao Feng Li, and Bang Chun Wen. "Design Object Planning of Vehicle NVH Performance Improvement Based on HOQ." Applied Mechanics and Materials 16-19 (October 2009): 229–33. http://dx.doi.org/10.4028/www.scientific.net/amm.16-19.229.

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Basing on the system engineering 7D design planning model included the seven aspects of contents: design ideas, design environment, design objective, design step, design content, design method and design quality assessment. Combined the 7D design planning with House of Quality (HOQ), the model of design objective planning model was presented. In the model the satisfied degree of customer was the optimization object. The customer needs were satisfied with the engineering characteristics. The customer needs were analyzed with the analytic hierarchy process. The correlation among engineering characteristics was considered through the improvement relation matrix. At the same time, each customer need was insured to improve with the limited resource. Contrasted with the general optimization model this design objective planning model took the correlation of engineering characteristics into account. This optimization model was applied successfully in the NVH (Noise, Vibration, and Harshness) improvement design of vehicle. The HOQ of NVH planning was established according to the four customer needs. The six engineering characteristics were confirmed corresponding to the customer needs. The results showed that the customer need degree achieved 75.53％. If the satisfied degree wanted to be improved the cost should be increased. In this design objective planning model the resource and technology were configured in reason. It could help the technician make the reasonable judgment.

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Sierzputowski, Gustaw, Radosław Wróbel, Veselin Mihaylov, Maciej Janeczek, Marta Majewska-Pulsakowska, and Sławomir Jarząb. "Pilot Studies of Vibrations Induced in Perambulators When Moving on Different Surfaces." Applied Sciences 11, no. 16 (August 23, 2021): 7746. http://dx.doi.org/10.3390/app11167746.

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The ergonomics of transport is a topic widely described in the literature. One of the fields of ergonomics that researchers are engaged in is vibrometry (both laser and accelerometry) of travel and its translation into NVH (Noise, Vibration and Harshness). However, so far, the influence of baby carriage movement on the generated vibrations has not been described in more detail. The topic seems to be particularly important considering occurrence of vibrations with significant amplitudes, whose frequency range can have a direct bearing on the resonance frequencies of the child’s internal organs. The article presents the results of research consisting in the measurement of vibrations to which an infant, lying in two different types of prams, may be exposed when being transported on different surfaces. The author’s measurement system, based on accelerometry, was used for the research. The obtained weighted RMS acceleration values not only exceeded human comfort level in all cases (according to ISO standard) but several times were in the range of the highest discomfort (>2 m/s2). Furthermore, the observed vibration frequency range (≈0 ÷ 32 Hz) coincided with the frequencies of free vibration of organs and parts of the child’s body.

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von Wysocki, Timo, Frank Rieger, Dimitrios Ernst Tsokaktsidis, and Frank Gauterin. "Generating Component Designs for an Improved NVH Performance by Using an Artificial Neural Network as an Optimization Metamodel." Designs 5, no. 2 (June 3, 2021): 36. http://dx.doi.org/10.3390/designs5020036.

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In modern vehicle development, suspension components have to meet many boundary conditions. In noise, vibration, and harshness (NVH) development these are for example eigenfrequencies and frequency response function (FRF) amplitudes. Component geometry parameters, for example kinematic hard points, often affect multiple of these targets in a non intuitive way. In this article, we present a practical approach to find optimized parameters for a component design, which fulfills an FRF target curve. By morphing an initial component finite element model we create training data for an artificial neural network (ANN) which predicts FRFs from geometry parameter input. Then the ANN serves as a metamodel for an evolutionary algorithm optimizer which identifies fitting geometry parameter sets, meeting an FRF target curve. The methodology enables a component design which considers an FRF as a component target. In multiple simulation examples we demonstrate the capability of identifying component designs modifying specific eigenfrequency or amplitude features of the FRFs.

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47

Kyprianou, A., J. Giacomin, K. Worden, M. Heidrich, and J. Bocking. "Differential evolution based identification of automotive hydraulic engine mount model parameters." Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering 214, no. 3 (March 1, 2000): 249–64. http://dx.doi.org/10.1243/0954407001527402.

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Hydraulic engine mounts are commonly used in automotive applications, and numerical models exist for performing full-vehicle noise, vibration and harshness (NVH) studies by means of multibody simulation. The parameters of these models are usually determined by the manufacturer from first-principle numerical calculations, or by means of direct testing of the individual components. This paper describes, instead, a four-step identification method developed to determine the parameter values of a specific hydromount numerical model, the Freudenberg hydromount equations, a set of highly non-linear piecewise-continuous differential equations. The identification procedure is based on two concepts, the first being the use of the differential evolution algorithm for determining optimal parameter values, while the second is the use of data obtained from a series of experimental tests of progressively higher displacement amplitude. Identified parameters provide models whose mean square errors between the calculated output force time history and the experimentally measured force time history are typically of the order of 1-2 per cent.

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Wang, Yawen, Junyi Yang, Dong Guo, and Teik C. Lim. "Vibration and sound radiation analysis of the final drive assembly considering the gear-shaft coupling dynamics." Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 230, no. 7-8 (February 17, 2016): 1258–75. http://dx.doi.org/10.1177/0954406216632021.

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A generalized dynamic model of driveline system is formulated that includes the coupling effect and gyroscopic moments of the propeller shaft and hypoid gear rotor assembly. Firstly, the dynamic models with only gear-shaft coupling, with only gyroscopic effect, and with both gear-shaft coupling and gyroscopic effect are analyzed and compared. The results show that the combined effects of the gear-shaft interaction and gyroscopic behavior have considerable influence on the system dynamic responses surrounding gear bending resonances, especially for the bearing responses. However, the gear out-of-phase torsional modes still dominate the gear mesh frequency response. Secondly, the influence of pinion bending moment of inertia, propeller shaft stiffness and bearing stiffness on the system dynamic responses are examined. The system responses are then applied to perform further vibration and acoustic analysis for an axle housing structure. Computational results reveal that NVH (noise, vibration, and harshness) refinement can be achieved by tuning the pinion bearing rotational stiffness and pinion bending moment of inertia for the example considered. This study provides an understanding of the interaction between hypoid gear pair and propeller shaft, and can be employed to enhance driveline system design.

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Yahaya Rashid, Aizzat S., Rahizar Ramli, Sallehuddin Mohamed Haris, and Anuar Alias. "Improving the Dynamic Characteristics of Body-in-White Structure Using Structural Optimization." Scientific World Journal 2014 (2014): 1–11. http://dx.doi.org/10.1155/2014/190214.

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The dynamic behavior of a body-in-white (BIW) structure has significant influence on the noise, vibration, and harshness (NVH) and crashworthiness of a car. Therefore, by improving the dynamic characteristics of BIW, problems and failures associated with resonance and fatigue can be prevented. The design objectives attempt to improve the existing torsion and bending modes by using structural optimization subjected to dynamic load without compromising other factors such as mass and stiffness of the structure. The natural frequency of the design was modified by identifying and reinforcing the structure at critical locations. These crucial points are first identified by topology optimization using mass and natural frequencies as the design variables. The individual components obtained from the analysis go through a size optimization step to find their target thickness of the structure. The thickness of affected regions of the components will be modified according to the analysis. The results of both optimization steps suggest several design modifications to achieve the target vibration specifications without compromising the stiffness of the structure. A method of combining both optimization approaches is proposed to improve the design modification process.

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Wei, Y. T., L. Nasdala, and H. Rothert. "Analysis of Tire Rolling Contact Response by REF Model." Tire Science and Technology 32, no. 4 (October 1, 2004): 214–35. http://dx.doi.org/10.2346/1.2186782.

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Abstract Analysis for tire dynamic response rolling over an obstacle is important to study automobile NVH (Noise-Vibration-Harshness), determine vehicle fatigue load, investigate combined longitudinal and sideslip properties, and develop ABS system on uneven roads. Based on the model of Ring on the Elastic and Viscoelastic Foundation (REF) and its analytical solution previously developed, the rolling contact problem between tire/flat and tire/cleat is dealt with in this paper. The static contact problem is treated as the first step to show the effectiveness and accuracy of the model. Then, the time domain simulation of tire rolling contact on uneven roads is conducted. Meirovitch modal analysis method and first-order matrix perturbation theory are applied to obtain the general forced response of damping REF vibration. An effective numerical quadrature method is developed to obtain the time-varying modal coordinates of the system under various loading conditions. Numerical examples of a tire rolling over a cleat are given to verify the developed method. It is found that both damping and velocity have strong effects on tire response over a cleat and the frequency of dynamic load is mainly controlled by the first tire mode.

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Journal articles on the topic 'Noise-vibration-harshness (NVH)'

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