Modeling and Validation of Rotational Vibration Responses for Accessory Drive Systems—Part I: Experiments and Belt Modeling

2013 ◽  
Vol 135 (3) ◽  
Author(s):  
Wen-Bin Shangguan ◽  
Xiang-Kun Zeng
Keyword(s):  
Friction Coefficient ◽  
Dynamic Stiffness ◽  
Excitation Frequency ◽  
Excitation Amplitude ◽  
Bending Stiffness ◽  
Damping Coefficient ◽  
Test Rig ◽  
Longitudinal Dynamic ◽  
Stiffness And Damping Coefficient ◽  
Stiffness And Damping

Experimental and modeling techniques for belt longitudinal static stiffness, longitudinal dynamic stiffness and damping coefficient, bending stiffness, and friction coefficient between a pulley and a belt are presented. Two methods for measuring longitudinal dynamic stiffness and damping coefficient of a belt are used, and the experimental results are compared. Experimental results show that the longitudinal dynamic stiffness of a belt is dependent on belt length, pretension, excitation amplitude and excitation frequency, and the damping coefficient of a belt is dependent on excitation frequency. Two models are presented to model the dependence of longitudinal dynamic stiffness and damping coefficient of a belt on belt length, pretension, excitation amplitude and excitation frequency. The proposed model is validated by comparing the estimated dynamic stiffness and damping with the experiment data. Also, the measurements of belt bending stiffness are carried out and the influences of the belt length on the belt bending stiffness are investigated. One test rig for measuring friction coefficient between a pulley and a belt are designed and fabricated, and the friction coefficient between the groove side belt with the groove side pulley, and the flat side belt with a flat pulley is measured with the test rig. The influences of wrap angle between pulley and belt, pretension of belt and rotational speed of the pulley on the friction coefficient are measured and analyzed. Taking an engine front end accessory drive system (FEAD) as the research example for the accessory drive system, experimental methods and the static and dynamic characteristics for the FEAD with seven pulleys, a tensioner, and a serpentine belt are presented.

Experimental study on dynamic performance of typical nonballasted track systems using a full-scale test rig

2016 ◽  
Vol 231 (4) ◽  
pp. 470-481 ◽  
Author(s):  
Mingze Wang ◽  
Chengbiao Cai ◽  
Shengyang Zhu ◽  
Wanming Zhai
Keyword(s):  
Experimental Study ◽  
Dynamic Stiffness ◽  
Dynamic Performance ◽  
Full Scale ◽  
Damping Coefficient ◽  
Full Scale Test ◽  
Test Rig ◽  
Scale Test ◽  
Stiffness And Damping Coefficient ◽  
Stiffness And Damping

This paper presents an experimental study on dynamic performance of China Railway Track System (CRTS) series track systems using a full-scale test rig. The test rig has been constructed based on 55.17 m long full-scale nonballasted tracks composed of four typical CRTS track elements in high-speed railways. First, the dynamic characteristics of different nonballasted tracks are investigated by conducting wheel-drop tests, where a wheel-drop testing vehicle with a dropping wheelset is devised to provide the wheel-drop load. The vibration levels of different track systems are assessed by the root-mean-square acceleration per one-third octave band, and the vibration transmission characteristics of the CRTS series tracks are evaluated by transfer functions. Further, a mathematical track model is used to extract the dynamic stiffness and damping coefficient of the four types of nonballasted track systems based on the wheel–rail impact response. The vibration characteristics, the dynamic stiffness, and damping coefficient of different nonballasted track systems under various wheel-drop heights are compared and discussed in detail.

Vibration of Elevator Cables With Small Bending Stiffness

2002 ◽  
Author(s):  
W. D. Zhu ◽  
G. Y. Xu
Keyword(s):  
Boundary Conditions ◽  
Bending Stiffness ◽  
Damping Coefficient ◽  
Lateral Vibration ◽  
Approximate Methods ◽  
Stiffness And Damping Coefficient ◽  
Stiffness And Damping ◽  
Optimal Stiffness

The effects of bending stiffness and boundary conditions on the lateral vibration of the stationary and moving hoist cables are investigated. The role of the trial functions in the approximate methods is examined. The optimal stiffness and damping coefficient of the suspension of the car against its guide rails are identified for the moving cable.

Dynamic Property Analysis of Rubber Absorber in Rail Fastenings of Different Force Condition

2012 ◽  
Vol 226-228 ◽  
pp. 877-880
Author(s):  
Shu Wei Wang ◽  
Yan Yun Luo ◽  
Li Li ◽  
Yan Liu
Keyword(s):  
Dynamic Property ◽  
Dynamic Stiffness ◽  
Testing Machine ◽  
Excitation Frequency ◽  
Least Square Method ◽  
Excitation Amplitude ◽  
Least Square ◽  
Model Parameters ◽  
Nonlinear Dynamic Model ◽  
Stiffness And Damping

This paper studies the dynamic property of rubber absorber in rail fastening by electro-hydraulic testing machine. Two different types of rail fastening are tested. In one fastening the rubber component is in compressed condition (RCRF). While in another the rubber is in sheared (RSRF). A nonlinear dynamic model of rubber absorber in rail fastening is proposed. The model parameters are obtained by the least square method. The accuracy of the obtained model is verified by measured result. The two results are in good agreement. The dynamic stiffness and damping are analyzed, and the results show that dynamic stiffness and damping are closely related to the frequency and amplitude of excitation. Nonlinear characteristic becomes greater with increasing excitation amplitude for the both rail fastenings. For different excitation frequency, the vibration reduction effect of RSRF is more stable than that of RCRF.

Design and structural performance measurements of a novel multi-cantilever foil bearing

2014 ◽  
Vol 229 (10) ◽  
pp. 1830-1838 ◽  
Author(s):  
Kai Feng ◽  
Xueyuan Zhao ◽  
Zhiyang Guo
Keyword(s):  
Dynamic Characteristics ◽  
Dynamic Load ◽  
Dynamic Stiffness ◽  
Excitation Frequency ◽  
Viscous Damping ◽  
Equivalent Viscous Damping ◽  
Foil Bearing ◽  
Load Tests ◽  
Stiffness And Damping ◽  
Motion Amplitude

With increasing need for high-speed, high-temperature, and oil-free turbomachinery, gas foil bearings (GFBs) have been considered to be the best substitutes for traditional oil-lubricated bearings. A multi-cantilever foil bearing (MCFB), a novel GFB with multi-cantilever foil strips serving as the compliant underlying structure, was designed, fabricated, and tested. A series of static and dynamic load tests were conducted to measure the structural stiffness and equivalent viscous damping of the prototype MCFB. Experiments of static load versus deflection showed that the proposed bearing has a large mechanical energy dissipation capability and a pronounced nonlinear static stiffness that can prevents overly large motion amplitude of journal. Dynamic load tests evaluated the influence of motion amplitude, loading orientation and misalignment on the dynamic stiffness and equivalent viscous damping with respect to excitation frequency. The test results demonstrated that the dynamic stiffness and damping are strongly dependent on the excitation frequency. Three motion amplitudes were applied to the bearing housing to investigate the effects of motion amplitude on the dynamic characteristics. It is noted that the bearing dynamic stiffness and damping decreases with incrementally increasing motion amplitudes. A high level of misalignment can lead to larger static and dynamic bearing stiffness as well as to larger equivalent viscous damping. With dynamic loads applied to two orientations in the bearing midplane separately, the dynamic stiffness increases rapidly and the equivalent viscous damping declines slightly. These results indicate that the loading orientation is a non-negligible factor on the dynamic characteristics of MCFBs.

Numerical analysis of the dynamic performance of aerostatic thrust bearings with different restrictors

2018 ◽  
Vol 233 (3) ◽  
pp. 406-423 ◽  
Author(s):  
Hailong Cui ◽  
Yang Wang ◽  
Xiaobin Yue ◽  
Yifei Li ◽  
Zhengyi Jiang
Keyword(s):  
Load Capacity ◽  
Dynamic Stiffness ◽  
Dynamic Performance ◽  
Dynamic Mesh ◽  
Eccentricity Ratio ◽  
Thrust Bearings ◽  
Stiffness And Damping Coefficient ◽  
Stiffness And Damping ◽  
The Impact ◽  
The Relationship

This study utilizes a dynamic mesh technology to investigate the dynamic performance of aerostatic thrust bearings with orifice restrictor, multiple restrictors, and porous restrictor. An experiment, which investigates the bearing static load capacity, was carried out to verify the calculation accuracy of dynamic mesh technology. Further, the impact of incentive amplitude, incentive frequency, axial eccentricity ratio, and non-flatness on the bearing dynamic performance was also studied. The results show incentive amplitude effect can be ignored at the condition of amplitude less than 5% film thickness, while the relationship between dynamic characteristics and incentive frequency presented a strong nonlinear relationship in the whole frequency range. The change law of dynamic stiffness and damping coefficient for porous restrictor was quite different from orifice restrictor and multiple restrictors. The bearing dynamic performance increased significantly with the growth of axial eccentricity ratio, and the surface non-flatness enhanced dynamic performance of aerostatic thrust bearings.

Research on the Tension Effects on Automobile Damping Synchronous Belt Transmission System Damping and Dynamic Stiffness

2014 ◽  
Vol 687-691 ◽  
pp. 407-410
Author(s):  
Yao Chen Shi ◽  
Zhan Guo Li ◽  
Dan Liu
Keyword(s):  
Solution Method ◽  
Dynamic Stiffness ◽  
Damping Coefficient ◽  
Stiffness Coefficient ◽  
Driving System ◽  
Automotive Engine ◽  
Vibration Absorption ◽  
Belt Transmission ◽  
Stiffness And Damping ◽  
Main Factor

because of the synchronism belts driving has the advantages of vibration absorption, noise reduction, constant transmission ratio, so it is widely used in automotive engine timing driving system, The stiffness and damping coefficients of the synchronous belt is the main factor affecting the synchronous belt transmission in the process of vibration and noise. In this paper, the model W automotive synchronous belt is simplified as a spring damper system, to solve the stiffness coefficient and damping coefficient of synchronous belt, design of a device for measuring the synchronous belt stiffness coefficient and damping coefficient, measured the belt stiffness coefficient and damping coefficient in the conditions of different tension, and the accuracy of the solution method for synchronous belt stiffness coefficient and damping coefficient was verified as well.

Study on Dynamics Characteristics of SINS Damping System in Shock Environment

2013 ◽  
Vol 397-400 ◽  
pp. 355-358
Author(s):  
Xia Qing Tang ◽  
Jun Qiang Gao ◽  
Li Bin Guo ◽  
Huan Zhang
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Optimal Design ◽  
Vibration Isolation ◽  
Damping Coefficient ◽  
Shock Environment ◽  
Stiffness And Damping Coefficient ◽  
Stiffness And Damping ◽  
Element Method

Dynamics characteristics of SINS damping system in shock environment were analyzed by finite element method, as the deformation of dampers may leads to the accuracy loss of SINS. In addition, the influence of absorber stiffness and damping coefficient on dynamics characteristics were studied. The results indicate that the decoupling of vibrations is significant for the accuracy of SINS. However, considering the almost impossible of completely decoupled vibrations, its necessary to carry out an optimal design of the absorber stiffness and damping coefficient to maintain the accuracy of SINS while meeting the requirement of vibration isolation.

EXPERIMENTAL INVESTIGATION OF A FOIL BEARING STRUCTURE WITH A POLYMER COATING UNDER DYNAMIC LOADS

Tribologia ◽  
2018 ◽  
Vol 281 (5) ◽  
pp. 5-12 ◽  
Author(s):  
Paweł BAGIŃSKI ◽  
Grzegorz ŻYWICA
Keyword(s):  
Excitation Frequency ◽  
Dynamic Loads ◽  
Test Rig ◽  
Static Tests ◽  
Structural Part ◽  
Foil Bearing ◽  
Wide Range ◽  
Load Tests ◽  
Excitation Force ◽  
Stiffness And Damping

This paper presents the results of research on the structural elements of a prototypical foil bearing in terms of its dynamic loads. In the framework of dynamic tests, several dozens of measurement series were carried out on a test rig specially prepared for this purpose. Dynamic excitations were applied using an electromagnetic exciter that enables changing the amplitude and frequency of the excitation force. Owing to this, it was possible to determine characteristics of the tested system in a wide range of loads and frequencies. A value of 400 Hz was assumed as the upper limit of the excitation frequency. The test rig enabled considering the direction of dynamic loads, which, as it turned out, had a significant impact on the obtained results. The research findings show that both the amplitude and frequency of an excitation force have a major impact on the stiffness and damping of the structural part of the foil bearing. The results of dynamic load tests complement the results of static tests performed earlier.

Structural Stiffness and Damping Coefficients of a Multileaf Foil Bearing With Bump Foils Underneath

2013 ◽  
Vol 136 (4) ◽  
Author(s):  
Ye Tian ◽  
Yanhua Sun ◽  
Lie Yu
Keyword(s):  
Excitation Frequency ◽  
Magnetic Bearing ◽  
Damping Capacity ◽  
Structural Stiffness ◽  
Test Rig ◽  
Domain Identification ◽  
Damping Coefficients ◽  
Foil Bearing ◽  
Applied Forces ◽  
Stiffness And Damping

This paper presents a multileaf foil bearing (MLFB), which consists of four resilient top foils and four stiff bump foils underneath; thus, a high supporting capacity and a high damping capacity can be achieved. A specially designed test rig is used to identify the structural stiffness and damping coefficients of the MLFB. The rotor of the test rig is supported by two journal MLFBs and a thrust active magnetic bearing (AMB) and the static and dynamic loads are applied by two radial AMBs. The tests on MLFBs were conducted under conditions of no shaft rotation at different angular positions and journal displacements with different excitation frequency. A frequency domain identification method is presented to determine the stiffness and damping coefficients. Static measurements show nonlinear deflections with applied forces, which varies with the orientation of the load angular position. The dynamic measurements show that the stiffness and equivalent viscous damping change with the excitation frequency. Furthermore, the stiffness and damping coefficients are related to the operating position where dynamic load tests were conducted. The investigation provides extensive measurements of the static and dynamic characteristics of the MLFB. These results can serve as a benchmark for the calibration of analytical tools under development.

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