Academic literature on the topic 'Modal Mass Participation Factor'
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Journal articles on the topic "Modal Mass Participation Factor"
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Agarwal, Abhishek, and Linda Mthembu. "Investigation of Dynamic Factors in Different Sections of HVC by Static and Free Vibration Modal Analysis." Annales de Chimie - Science des Matériaux 46, no. 2 (April 30, 2022): 75–84. http://dx.doi.org/10.18280/acsm.460203.
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One of the essential purposes of the automotive chassis is to maintain the vehicle's shape and bear the various loads applied to the vehicle. When a heavy-duty vehicle, e.g., a truck, travels on the road, the chassis is subject to vibrations produced by surface roughness and excitation due to the vibration of body parts. The present study aims to design, model, and perform a static structural & vibrational modal analysis on a commercial vehicle (Truck) chassis considering both conventional Structural steel and P100/6061 Al Metal Metrix Composite (MMC) using ANSYS CFX to determine the strength of chassis with transverse sections. Free vibrational modal analysis determines the mass participation factor and resonance frequency for square section and C section, respectively, for both materials using the finite element technique. It was observed that the use of the C section causes an increase in deformation for all the natural frequencies, which is not preferred. The high mass participation factor along the x-direction signifies that any external excitation along this direction would likely cause resonance and amplitude build-up. The C section profile of the chassis shows 1.69% higher deformation than the square section in both cases; hence it is not desirable for the design.
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Agrahari, Ravinder Kumar, and K. K. Pathak. "Comparative Study of Seismic Acceleration Amplification Models for RC Frame Structures." IOP Conference Series: Materials Science and Engineering 1197, no. 1 (November 1, 2021): 012044. http://dx.doi.org/10.1088/1757-899x/1197/1/012044.
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Abstract As the current aspect, the nonstructural components (NSCs) linked with the structures are more affected during the seismic motion. It causes not only loss of the economy but also affected life. The various codal provision has been available for minimizing the damages of primary components, but for NSCs, a minimal requirement is functional. So that more investigation is required for understating the behavior of NSCs during the seismic motion. The research aims to understand the behavior of acceleration demand on NSCs in a building. Structures subjected to inertia forces due to earthquakes experience damage of nonstructural components (NSC). The inertia force acting the NSCs are related to acceleration amplification factor. For obtaining the peak horizontal floor acceleration with respect to tectonic ground motion, these factors are used. In this paper, mathematical models of the acceleration amplification factor defined as the peak floor acceleration with respect to peak ground acceleration, given by previous researchers, has been compared. For this 2,4,6,8 and 10 storey moment-resisting frame models considering 29 ground motion data ranging between 0.1g to 0.2g, is analyzed using linear time history method. The supports of the models are considered fixed. The ETABS software is used for the analysis of the models. To analyses the models, the modal mass participation ratio plays a significant role. ASCE 7-05 defines that the structure should be investigated and designed when the model mass participation ratio is equal to or more than 90 per cent. Based on the results, a comparison of the reported models is made. There is a strong need for further research to refine the models for the realistic prediction of acceleration amplification factor.
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Shen, Botan, Jin Wang, Weibing Xu, Yanjiang Chen, Weiming Yan, Jianhui Huang, and Zhenyun Tang. "Experimental Research on Damping Effect of Double-Layer Tuned Mass Damper for High-Rise Structure." Shock and Vibration 2021 (December 2, 2021): 1–22. http://dx.doi.org/10.1155/2021/7523127.
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A double-layer tuned mass damper (DTMD) has advantages of wide damping frequency band and strong robustness. At present, there is a lack of seismic design methods for high-rise structures based on DTMDs. In this study, a DTMD parameter optimisation method was proposed, with the objective of minimising the peak displacement response of a first N-order vibration modal with a vibration mass participation factor of 85%. Then, a scale model of a high-rise structure was fabricated, along with a corresponding DTMD. Different types of excitations were chosen to clarify the dynamic responses of the model with and without the DTMD, including Site-II ground motions, long-period (LP) ground motions without pulses, and near-fault pulse-type (NFPT) ground motions. The results indicate that the dynamic responses of high-rise structures under LP and NFPT ground motions are much greater than those under Site-II ground motions. The DTMD can effectively reduce the absolute displacement response, acceleration response, and strain response at the top floor of the test model. However, the DTMD has a time delay in providing the damping effect. A smaller damping ratio between the upper TMD and the controlled structure will lead to a more significant damping effect for the DTMD.
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Chaudhari, Mr Rohit Kiran. "Non-Linear Time History Analysis of an Elevated Water Tank." International Journal for Research in Applied Science and Engineering Technology 9, no. VI (June 30, 2021): 4327–34. http://dx.doi.org/10.22214/ijraset.2021.35939.
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It was discovered that reinforced concrete elevated water tanks with frame staging outperformed reinforced concrete elevated water tanks with shaft staging in terms of seismic resistance. These can be due to the frame staging's seismic energy absorption capability. As a result, the primary goal of this research is to better understand the seismic behavior and performance characteristics of elevated water tanks with frame staging. Furthermore, when compared to other shapes, circular tanks have the smallest surface area for a given tank size. As a result, the amount of material needed for a circular water tank is less than for other shapes. As a result, a circular water tank was chosen, and seismic analysis of elevated RC circular water tanks was carried out according to IITK-GSDMA guidelines, with the behavior of the water tank analysed for various parameters such as zone factor, soil condition, and different staging heights. SAP 2000 was used to determine the structure's modal characteristics (mode shapes and modal participation mass ratio).
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Shah, Dhara, and Jaimin Padia. "Seismic Evaluation of RC Building with Vertical Setbacks as per IS1893 (Part 1):2016." Proceedings of the 12th Structural Engineering Convention, SEC 2022: Themes 1-2 1, no. 1 (December 19, 2022): 687–91. http://dx.doi.org/10.38208/acp.v1.569.
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Earthquake forces are the least predictable and most devastating form of forces. These forces are not only responsible for loss of economy, property and material but possess a huge threat to lives of people as well. In past several years, severe damages to buildings and causalities have been witnessed due to these disastrous forces there by challenging the designing and construction authorities. Many buildings are designed with vertical setbacks due to architectural, functional or economic reasons wherein fewer stories in a building are wider than rest of the building. Such setbacks in buildings cause sudden jump in seismic forces at the level of discontinuity due to change in stiffness, mass and strength distribution along height. This might lead to torsion in the building under seismic forces. Structures incorporating vertical irregularities need to be studied for their behavioural aspects, identifying the weak links which might trigger the collapse. In the present study, effect of vertical geometric irregularities in a building is studied with respect to a regular building using equivalent static method and response spectrum method as per IS1893 (Part 1): 2016. The results obtained are compared in terms of displacements, storey drift, base shear, forces, modal time period, modal mass participation factor and % increase in structural members along with concrete quantity.
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Ghasemloonia, Ahmad, D. Geoff Rideout, and Stephen D. Butt. "Coupled transverse vibration modeling of drillstrings subjected to torque and spatially varying axial load." Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 227, no. 5 (August 3, 2012): 946–60. http://dx.doi.org/10.1177/0954406212455126.
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Predicting and mitigating unwanted vibration of drillstrings is an important subject for oil drilling companies. Uncontrolled vibrations cause premature failure of the drillstring and associated components. The drillstring is a long slender structure that vibrates in three primary coupled modes: torsional, axial and transverse. Among these coupled modes, the transverse mode is the major cause of drillstring failures and wellbore washout. Modal analysis of drillstrings reveals critical frequencies and helps drillers to avoid running the bit near critical modes. In this article, the coupled orthogonal modes of transverse vibration of a drillstring in the presence of torque and spatially varying axial force (due to mud hydrostatic effect, self-weight and hook load) are derived and the mode shapes and natural frequencies are determined through the expanded Galerkin method. The results are verified by the nonlinear finite element method. Modal mass participation factor, which represents how strongly a specific mode contributes to the motion in a certain direction, is used to determine the appropriate number of modes to retain so that computational efficiency can be maximized.
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Yang, Pengchao, Songtao Xue, Liyu Xie, and Miao Cao. "Damping Estimation of an Eight-Story Steel Building Equipped with Oil Dampers." Applied Sciences 10, no. 24 (December 16, 2020): 8989. http://dx.doi.org/10.3390/app10248989.
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The damping estimation of an eight-story steel building equipped with oil dampers is examined, carried out by adopting a proposed framework, which consists of an enhanced strain-energy method and an improved direct method for model updating. The building is located at Tohoku Institute of Technology and is equipped with a structural monitoring system that measures its seismic response, including floor acceleration and displacement and force of oil dampers. The enhanced strain-energy method is first developed and employed to assess the supplemental damping and stiffness provided by oil dampers, herein quantified in the form of equivalent damping ratios and natural frequencies. Then, modal characteristics extracted from the earthquake measurements are modified accordingly and utilized for the building model updating, in which mass and stiffness matrices are corrected by the improved direct method. The updated model accurately reproduces the target modal data, especially measured mode participation factors, and is further used for the building response predictions. Through prediction validations, the precision of the modified modal parameters is verified. Finally, a large earthquake event is chosen to demonstrate the effectiveness of the proposed framework for the damping estimation of the investigated building.
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Parihar, Abhyuday. "Modelling, FEA analysis and Optimization of Mono Composite Leaf Spring Using ANSYS." International Journal for Research in Applied Science and Engineering Technology 9, no. 12 (December 31, 2021): 2127–33. http://dx.doi.org/10.22214/ijraset.2021.39690.
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Abstract: Conventional leaf spring made up of conventional materials like plain carbon steel are heavy and add weight to vehicle which reduces mileage. This necessitates new material which is light in weight and could provide adequate strength to leaf spring along with higher strain energy absorption to absorb shocks. The current research is intended to study the structural and vibrational characteristics of leaf spring made of P100/6061 Al, P100/AZ 91C Mg and structural steel materials. The investigation is carried out using ANSYS FEA software. The FEA results have shown that P100/AZ/ 91C generated lower stresses as compared to P100/6061 Al and structural steel material. The modal analysis of leaf spring aided to determine mass participation factor and mode shapes corresponding to each frequency. Keywords: Leaf Spring, Energy Absorption, Structural Steel Materials, ANSYS FEA, Frequency.
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Gao, Bo, Zhihui Bai, and Yubo Song. "Optimal Three-Dimensional Sensor Placement for Cable-Stayed Bridge Based on Dynamic Adjustment of Attenuation Factor Gravitational Search Algorithm." Shock and Vibration 2021 (March 31, 2021): 1–14. http://dx.doi.org/10.1155/2021/6664188.
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Structural health monitoring (SHM) is essential when detecting damage in large and complex structures in order to provide a comprehensive assessment of the structural health state. Optimal sensor placement (OSP) is critical in the structural health monitoring system, which aims to use a limited number of sensors to obtain high-quality structural health diagnosis data. However, the current research mainly focuses on OSP for structures, without considering the values contributed by different modes to the bridge structure. In this article, an optimal sensor placement method based on initial sensor layout, using the dynamic adjustment of attenuation factor gravitational search algorithm (DGSA), is proposed. The effective modal mass participation ratio is introduced to ensure the validity of the initial data of optimal sensor placement. In view of the insufficient developmental ability of the gravitational search algorithm, the attenuation factor α adjusted dynamically aids the global search in the early iteration and the local fine search in the late iteration. The double coding method is used to apply the DGSA algorithm to OSP; taking cable-stayed bridges as an example, the feasibility of the algorithm is verified. The results show that the improved algorithm has a good optimization ability and can accurately and efficiently determine the optimal placement of sensors.
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mohiuddin, Syed Mohammed, Mohammed moiz, Mohammed khaja moinuddin, and Mohammed Tosif Ahmed. "DYNAMIC ANALYSIS AND DESIGN OF MULTISTOREYED R.C STRUCTURAL FRAME WITH PILE FOUNDATION." International Journal of Innovative Research in Advanced Engineering 8, no. 6 (June 30, 2021): 120–30. http://dx.doi.org/10.26562/ijirae.2021.v0806.001.
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The structure is presumed to be situated in seismic Zones II and V. The mathematical building model (F.E.M Model) of Whole building has been modelled in ETABS 16.2 All the beams and columns are modelled as frame elements. All the slabs are modelled as thin shell elements. To ascertain the seismic load on each floor level of whole structure two types of seismic analysis procedure have been considered as per IS1893-2002 and 2016. Equivalent static approach (linear Static method) and Response spectrum method (Linear Dynamic Method). Parameters considered to understand the seismic response of the multi-storeyed buildings are, Modal Mass participation factor, Modal time period, Lateral displacement, Storey drift, Storey shear of the structure. The whole structural systems are strengthen with vertical shear walls. SAFE (Slab analysis by Finite Element Method) is a software essentially made for analyse and designs of the slabs, since Pile Raft is also a slab therefore SAFE is the ultimate tool for it. Pile Caps have modelled as Slab with Thick plate Action, for base reactions Link between ETABS and SAFE have been used. The parameters consider for finalise the designs of piles and pile caps are, vertical settlement, Punching Shear stress under columns and shear walls and for piles as well. Flexural reinforcements are tabulated in both Longitudinal and transvers direction for the both the faces i.e. Top face and bottom. After all the study a comparison is made between the structure situated in Zone II and Zone V We had observed that when the seismic zones changes and the intensity of seismic forces increases, the design of foundation considerably changes and there is tremendous amount of increase in steel.
Dissertations / Theses on the topic "Modal Mass Participation Factor"
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Case, Justin J. "Numerical analysis of the vibration and acoustic characteristics of large power transformers." Thesis, Queensland University of Technology, 2017. https://eprints.qut.edu.au/103702/1/Justin_Case_Thesis.pdf.
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This thesis presents a numerical methodology to predict the noise and vibration characteristics of large power transformers. The approach, which focuses on a vibro-acoustic finite element simulation, has been validated by appropriate experimental measurements and is shown to identify both the local and global acoustic behaviour of a transformer under nominal operating conditions. Furthermore, analysis methods presented in this thesis have illustrated a transformer's complex vibration characteristics that result in elevated noise levels. An understanding of such vibration characteristics together with acoustic predictions will better enable transformer manufacturers to consistently meet noise emission targets set by customers and regulators.
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Jakel, Roland. "Linear Dynamic System Analyses with Creo Simulate – Theory & Application Examples, Capabilities, Limitations –." Universitätsbibliothek Chemnitz, 2017. http://nbn-resolving.de/urn:nbn:de:bsz:ch1-qucosa-225992.
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1. Einführung in die Theorie dynamischer Analysen mit Creo Simulate 2. Modalanalysen (Standard und mit Vorspannung) 3. Dynamische Analysen einschließlich Klassifizierung der Analysen; einige einfache Beispiele für eigene Studien (eine Welle unter Unwuchtanregung und ein Ein-Massen-Schwinger) sowie etliche Beispiele größerer dynamischer Systemmodelle aus unterschiedlichsten Anwendungsbereichen 4. Feedback an den Softwareentwickler PTC (Verbesserungsvorschläge und Softwarefehler) 5. Referenzen1. Introduction to dynamic analysis theory in Creo Simulate 2. Modal analysis (standard and with prestress) 3. Dynamic analysis, including analysis classification, some simple examples for own self-studies (shaft under unbalance excitation and a one-mass-oscillator) and several real-world examples of bigger dynamic systems 4. Feedback to the software developer PTC (enhancement requests and code issues) 5. References
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Ozcebe, Ali Guney. "A Comperative Assessment Of Available Methods For Seismic Performance Evaluation Of Buried Structures." Master's thesis, METU, 2009. http://etd.lib.metu.edu.tr/upload/12610857/index.pdf.
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In the last three decades, seismic performance assessment of buried structures has evolved through the following stages : i) buried structures are not prone to seismically-induced damages, thus no need for detailed investigations, ii) eliminating soil-structure-earthquake interaction and use of seismically-induced free field ground deformations directly as the basis for seismic demand, thus producing conservative results, and finally iii) soil-structure and earthquake interaction models incorporating both kinematic and inertial interactions. As part of soil-structure and earthquake interacting models, simplified frame analysis established the state of practice and is widely used. Within the confines of this thesis, the results of simplified frame analysis based response of buried structures are compared with those of 2-D finite element dynamic analyses. For the purpose, 1-D dynamic and 2-D pseudo-dynamic analyses of free field and buried structural systems are performed for a number of generic soil, structure and earthquake combinations. The analyses results revealed that, in general, available closed form solutions are in pretty good agreement with the results of finite element analyses. However, due to the fact that dynamic analyses can model both kinematic and inertial effectsit should be preffered for the design of critical structures.
Books on the topic "Modal Mass Participation Factor"
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Sang-in, Chŏn, ed. Hanʼguk hyŏndaesa: Chinsil kwa haesŏk. Kyŏnggi-do Pʻaju-si: Nanam Chʻulpʻan, 2005.
Find full textBook chapters on the topic "Modal Mass Participation Factor"
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Camponovo, Giovanni, Anna Picco-Schwendener, and Lorenzo Cantoni. "Motivations and Barriers of Participation in Community Wireless Networks." In Social and Economic Effects of Community Wireless Networks and Infrastructures, 112–34. IGI Global, 2013. http://dx.doi.org/10.4018/978-1-4666-2997-4.ch007.
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Wireless communities are an interesting alternative to 3G networks to provide mobile Internet access. However, the key success factor for their sustainability is whether they are able to attract and retain a critical mass of contributing members. It is thus important to understand what motivates and dissuades people to join and participate. This chapter analyzes motivations, concerns, usage, and satisfaction of members of Fon. Fon is the largest wireless community in the world. This study employs a mixed research method, combining qualitative exploratory interviews with a quantitative survey. Members are mainly motivated by a mix of utilitarian (getting free connectivity) and idealistic motivations (reciprocity and altruism), whereas intrinsic and social motivations are less relevant.
Conference papers on the topic "Modal Mass Participation Factor"
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Ly, B. L., and Y. An. "Response Spectrum Method for Submerged Structures." In ASME 2008 Pressure Vessels and Piping Conference. ASMEDC, 2008. http://dx.doi.org/10.1115/pvp2008-61054.
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A submerged structure has virtual mass matrix in the inertial term and wet mass matrix in the driving term in the equation of motion, whereas a dry structure has the same mass matrix in these two terms. If a finite element code for dry structures is used to analyze a submerged structure, the results should be adjusted. Result for a Single Degree of Freedom (SDOF) system is scaled by the ratio of wet mass to virtual mass. Results for a Multiple Degree of Freedom (MDOF) system are adjusted by scaling the Floor Response Spectra (FRS) at each modal frequency by a ratio of modal work done in that mode by the wet mass matrix to that by the virtual mass matrix. The adjustment factor can be estimated as a product of a ratio of participation factors and a ratio of modal masses. Both the participation factors and the modal masses are computed by using the wet mass matrix, and then by using the virtual mass matrix, respectively. This method provides an alternative way to assess the margin in the design based on the current FRS method that does not distinguish the difference between the two mass matrices. More studies should be carried out to implement this method in specific practical applications.
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Xiong, X., and S. O. Oyadiji. "Optimized Mechanical Performance of Cantilevered Vibration Energy Harvesters Using a Modal Approach." In ASME 2014 12th Biennial Conference on Engineering Systems Design and Analysis. American Society of Mechanical Engineers, 2014. http://dx.doi.org/10.1115/esda2014-20620.
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In order to improve the performance of cantilevered vibration energy harvesters, current methods normally vary their geometric dimensions and derive the maximum power outputs by running a full analysis. This paper attempts to optimize the structural performance of cantilevered vibration energy harvesters using a modal approach without carrying out full analysis. The effects of varying geometrical dimensions on the modal mechanical performance are analysed, which includes the analysis on rectangular cantilevered beams with and without extra mass, the convergent and divergent tapered cantilevered beams. The modal approach uses mass ratio and the modal electromechanical coupling coefficient to determine the electrical and mechanical modal performance of vibration energy harvesters. In particular, mass ratio depends on the modal participation factor, and it represents the influence of modal mechanical behaviour on the power density directly. The required modal parameters are derived using the finite element method and a distributed parameter electromechanical model is also used for comparison. The cantilevered beam designs using the modal approach can be used with different sizes with the power ranging from microwatts to milliwatts.
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Schedlinski, Carsten, and Michael Link. "Identification of Frequency Response Functions and Modal Data From Base Excitation Tests Using Measured Interface Forces." In ASME 1995 Design Engineering Technical Conferences collocated with the ASME 1995 15th International Computers in Engineering Conference and the ASME 1995 9th Annual Engineering Database Symposium. American Society of Mechanical Engineers, 1995. http://dx.doi.org/10.1115/detc1995-0521.
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Abstract Base excitation testing is used in industry in order to qualify mechanical systems with respect to specified base acceleration levels. This type of excitation only allows to identify eigenfrequencies, mode shapes and modal damping values of the fixed/free system. Modal masses, mass participation factors and effective masses of the fixed/free system as well as the modal data of the free/free system cannot be identified because the excitation forces are unknown. This paper introduces an approach to identify these modal data as well. For this purpose the reaction forces at the table/structure interface have to be measured also. Furthermore, the verification of the theory using a laboratory test structure will be presented.
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Thompson, Thomas J. "Spherical Compliant Model for Vibration Estimation and Control." In ASME 1995 Design Engineering Technical Conferences collocated with the ASME 1995 15th International Computers in Engineering Conference and the ASME 1995 9th Annual Engineering Database Symposium. American Society of Mechanical Engineers, 1995. http://dx.doi.org/10.1115/detc1995-0577.
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Abstract Proposed space missions involve large structures which must maintain precise dimensional tolerances during dynamic maneuvers. In order to attenuate disturbances in the many modes of vibration of such structures, active and passive vibration control has been proposed. Passive control is to be achieved by placing viscous or viscoelastic members in a structure to absorb energy, while active control similarly could involve structural members (struts) capable of sensing axial displacement and exerting axial control force. With conventional modal analysis, the effect of a control element on a system is computed by summing its influence on many immutable modes. Since changes in mode shape must be described by this summation, truncation of higher modes results in inaccuracies. The compliant model of vibration to be presented accurately accounts for the effects of locally-acting control elements without inclusion of high-frequency modes. The motion of each spring-mass system representing a structural mode is modified by a control element in series with another stiffness inherent to the structure for that mode and control position. In order to predict the influence of several control elements or dampers on closely-spaced modes, the compliant models for those modes are integrated into a spherical model in which one lumped mass is acted upon by orthogonal modal stiffnesses. In the spherical model, control elements influent the lumped mass from orientations determined by mode participation factors. The resulting equations of motion are stated in standard state-space form. To test accuracy, the compliant model is used to predict eigenvalue shifts due to springs and dampers acting upon an axially-vibrating rod, and the spherical model is used to predict damping accurately in a lumped-mass system with closely-spaced modes.
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Baek, Seunghun, Yixin Zhao, and Bogdan Epureanu. "Reduced Order Models of Blisks With Small Geometric Mistuning." In ASME Turbo Expo 2016: Turbomachinery Technical Conference and Exposition. American Society of Mechanical Engineers, 2016. http://dx.doi.org/10.1115/gt2016-57829.
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A technique for generating reduced order models (ROMs) of bladed disks with small geometric mistuning is proposed. Discrepancies in structural properties (mistuning) from blade to blade can cause a significant increase in the maximum vibratory stress. The effects of mistuning have been studied over the past few decades. Many researchers have studied the dynamic behavior of mistuned bladed disks by using ROMs. Many of these techniques rely on the fact that the modes of a mistuned system can be approximated by a linear combination of modes of the corresponding tuned system. Also, the tuned system modes have been modeled in component mode mistuning by using modal participation factors of cantilevered blade modes. Such techniques assume that mistuning can be well modeled as variations in blade alone frequencies. However, since geometric deformations contain stiffness and mass variations, mistuning can no longer be captured by cantilevered blade modes alone. To address this, a new technique is presented for generating ROMs of bladed disks with small geometric mistuning which may be a more general case of mistuning in practice.
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Arief, A., M. B. Nappu, A. Nizar, and Z. Y. Dong. "Determination of DG allocation with modal participation factor to enhance voltage stability." In 8th International Conference on Advances in Power System Control, Operation and Management (APSCOM 2009). IET, 2009. http://dx.doi.org/10.1049/cp.2009.1850.
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Li, Huiyu, Hua Li, and Hornsen Tzou. "Neural-Network Vibration Control of Rings With Light-Activated Shape Memory Polymer Actuators." In ASME 2015 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference. American Society of Mechanical Engineers, 2015. http://dx.doi.org/10.1115/detc2015-47019.
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The light-activated shape memory polymer (LaSMP) is sensitive to ultraviolet light with specific wavelength. It is featured with dynamic stiffness. In this study, LaSMP is used to control the vibration of thin ring shells induced by external loading. Firstly the variation of LaSMP’s Young’s modulus is modeled. The mathematical model reflects the influence of light intensity, the decay coefficient and thickness of LaSMP. Besides, the model is suitable for LaSMPs with different reaction orders. Then, with Lamé parameters and the radii of rings the governing equations of the flexible ring laminated with LaSMP actuators are established. Love operators of LaSMP actuators are derived. Based on the mode expansion method, the modal forces of external loading and LaSMP actuators are given. The modal participation factors are analyzed with the modal forces. As the variation of Young’s modulus to the light intensity is nonlinear, the control effect of LaSMP actuators to common harmonic excitation is not perfect. Because the neural network control is effective to identify complex models, it is introduced to adjust the profile of light intensity. In the case study, the model of LaSMP’s Young’s modulus is validated with the experimental data. Then the forced harmonic responses of the ring are studied. For the mode n=2, the modal participation factor is reduced by 47.7% with the control of LaSMP actuator. To further enhance the control effect, the phase shift method is applied. With π/6 phase shift, the modal participation factor is reduced by 80.8%. With the neural network control method, the modal participation factor is cut down by 98.1%. The study shows that LaSMP actuator provides a new choice to control the forced vibration of flexible rings. It is also possible to apply LaSMP actuator to vibration control of other thin shell structures.
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Ren, Jun, Jun Wang, Kwun-Lon Ting, Quan Wang, Qiong Wei, and Jinfeng Sun. "Calibration of Measured FRFs Based on Mass Identification Method." In ASME 2015 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference. American Society of Mechanical Engineers, 2015. http://dx.doi.org/10.1115/detc2015-48061.
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It is necessary to calibrate the equipment during each test in modal testing. This paper presented a practical method for the calibration of the measured FRFs based on mass identification method. One advantage of this proposed method is that the calibration is performed directly on the test structure. Thus, it is more reliable and convenient. It is shown that if the mass identification method is applied to the uncalibrated system, a different level between the identified mass and the given exact mass reveals that the set up is not calibrated. And the measured FRFs can be calibrated using the ratio factor of the identified mass and exact mass. The simulation testing demonstrates good performance. In practical testing, however, the accuracy of mass identification results may be vulnerable to the noise and further work is necessary in order to solve this difficulty.
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Li, H., Z. B. Chen, S. D. HU, and H. S. Tzou. "Optimal Control of Clamped-Free Conical Shell Using Diagonal Piezoelectric Sensor and Actuator." In ASME 2011 International Mechanical Engineering Congress and Exposition. ASMEDC, 2011. http://dx.doi.org/10.1115/imece2011-63028.
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In this paper, optimal vibration control of a clamped-free conical shell is presented. A diagonal piezoelectric sensor/actuator (S/A) pair is proposed to control the axial, bending and transverse vibrations of the conical shell. The modal functions are adapted to satisfy the clamped-free boundary condition. Based on the independent modal control method, the response of conical shell to external excitations can be represented by the summation of all participating natural modes and their respective modal participation factors and each mode can be controlled independently. The modal equation is transformed into the linear state space form. The modal participation factor and its time derivative are chosen to be the state variables. The sensing signals are chosen to be the output vector. The modal force is chosen to be the control input vector. The linear quadratic (LQ) controllers are designed for each independent mode. The optimal gain matrix is related to the ratio between control voltage and sensing signal by the modal control force per unit voltage and the sensing signal. Numerical examples show that, the proposed optimal control method can achieve significant active control effects and the optimal gains are mainly related to the modal velocity. This effect varies with the locations of S/A pair and the mode of the shell. The results indicate that, to achieve the best control effects for all wanted modes, the optimal controller and the optimization of the S/A location should be taken into account in the design of the optimal controller.
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Tamura, Ichiro, and Shinji Tamura. "Relationship Between Natural Period, Strength, and Response Of Piping Systems Subjected to Seismic Motion." In ASME 2022 Pressure Vessels & Piping Conference. American Society of Mechanical Engineers, 2022. http://dx.doi.org/10.1115/pvp2022-83884.
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Abstract The relationship between the natural period, strength, and the response of piping systems subjected to seismic motion was investigated for straight piping systems and piping systems with elbows. The strength of each mode of a piping system subjected to seismic motion, or seismic inertia force, is represented by the modal yield acceleration, that is, the modal yield strength normalized by the modal mass. The response of that is represented by the modal ductility factor, that is, the ductility factor of the first yielding part of the piping system in its mode. The relationship between the natural period and modal yield acceleration is represented by the proposed piping yield diagram. The relationship between the natural period, modal yield acceleration, and the response is represented by the well-known inelastic response spectrum, or constant-ductility response spectrum. Using these diagrams and spectra, the responses of piping systems to various seismic motions could be estimated without performing individual dynamic analyses of them.
Reports on the topic "Modal Mass Participation Factor"
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Friedman, Haya, Julia Vrebalov, James Giovannoni, and Edna Pesis. Unravelling the Mode of Action of Ripening-Specific MADS-box Genes for Development of Tools to Improve Banana Fruit Shelf-life and Quality. United States Department of Agriculture, January 2010. http://dx.doi.org/10.32747/2010.7592116.bard.
Full textAbstract:
Fruit deterioration is a consequence of a genetically-determined fruit ripening and senescence programs, in which developmental factors lead to a climacteric rise of ethylene production in ethylene-sensitive fruits such as tomato and banana. Breeding of tomato with extended fruit shelf life involves the incorporation of a mutation in RIN, a MADS-box transcription factor participating in developmental control signalling of ripening. The RIN mode of action is not fully understood, and it may be predicted to interact with other MADS-box genes to execute its effects. The overall goal of this study was to demonstrate conservation of ripening control functions between banana and tomato and thus, the potential to genetically extend shelf-life in banana based on tools developed in tomato. The specific objectives were: 1. To increase the collection of potential RIN-like genes from banana; 2. To verify their action as developmental regulators; 3. To elucidate MADS-box gene mode of action in ripening control; 4. To create transgenic banana plants that express low levels of endogenous Le-RIN- like, MaMADS- gene(s). We have conducted experiments in banana as well as in tomato. In tomato we have carried out the transformation of the tomato rin mutant with the MaMADS1 and MaMADS2 banana genes. We have also developed a number of domain swap constructs to functionally examine the ripening-specific aspects of the RIN gene. Our results show the RIN-C terminal region is essential for the gene to function in the ripening signalling pathway. We have further explored the tomato genome databases and recovered an additional MADS-box gene necessary for fruit ripening. This gene has been previously termed TAGL1 but has not been functionally characterized in transgenic plants. TAGL1 is induced during ripening and we have shown via RNAi repression that it is necessary for both fleshy fruit expansion and subsequent ripening. In banana we have cloned the full length of six MaMADS box genes from banana and determined their spatial and temporal expression patterns. We have created antibodies to MaMADS2 and initiated ChI assay. We have created four types of transgenic banana plants designed to reduce the levels of two of the MaMADS box genes. Our results show that the MaMADS-box genes expression in banana is dynamically changing after harvest and most of them are induced at the onset of the climacteric peak. Most likely, different MaMADS box genes are active in the pulp and peel and they are differently affected by ethylene. Only the MaMADS2 box gene expression is not affected by ethylene indicating that this gene might act upstream to the ethylene response pathway. The complementation analysis in tomato revealed that neither MaMADS1 nor MaMADS2 complement the rin mutation suggesting that they have functionally diverged sufficiently to not be able to interact in the context of the tomato ripening regulatory machinery. The developmental signalling pathways controlling ripening in banana and tomato are not identical and/or have diverged through evolution. Nevertheless, at least the genes MaMADS1 and MaMADS2 constitute part of the developmental control of ripening in banana, since transgenic banana plants with reduced levels of these genes are delayed in ripening. The detailed effect on peel and pulp, of these transgenic plants is underway. So far, these transgenic bananas can respond to exogenous ethylene, and they seem to ripen normally. The response to ethylene suggest that in banana the developmental pathway of ripening is different than that in tomato, because rin tomatoes do not ripen in response to exogenous ethylene, although they harbor the ethylene response capability This study has a major contribution both in scientific and agricultural aspects. Scientifically, it establishes the role of MaMADS box genes in a different crop-the banana. The developmental ripening pathway in banana is similar, but yet different from that of the model plant tomato and one of the major differences is related to ethylene effect on this pathway in banana. In addition, we have shown that different components of the MaMADS-box genes are employed in peel and pulp. The transgenic banana plants created can help to further study the ripening control in banana. An important and practical outcome of this project is that we have created several banana transgenic plants with fruit of extended shelf life. These bananas clearly demonstrate the potential of MaMADS gene control for extending shelf-life, enhancing fruit quality, increasing yield in export systems and for improving food security in areas where Musaspecies are staple food crops.