scholarly journals Modeling and Dynamics Analysis of a Dual-Mass Flywheel with the Conformal Contact Action of Friction Damping Ring and Pressure Plate

2021 ◽  
Vol 2021 ◽  
pp. 1-17
Author(s):  
Liping Zeng ◽  
Jie Huang ◽  
Yukun Xu ◽  
Liquan Song
Keyword(s):  
Nonlinear Dynamic ◽  
Angular Displacement ◽  
Frequency Characteristics ◽  
Degree Of Freedom ◽  
Response Analysis ◽  
Torsional Angle ◽  
Nonlinear Frequency ◽  
Friction Damping ◽  
Pressure Plate ◽  
Conformal Contact

To study the nonlinear dynamic characteristics of the dual-mass flywheel (DMF) under the conformal contact action between the friction damping ring and primary flywheel pressure plate, the contact action model is established and analyzed based on Winkler model. Through analysis and calculation, the contact deformation, contact pressure at different contact positions, and equivalent torsional contact stiffness are obtained. The nonlinear dynamic analysis model of three-degree-of-freedom (3DOF) which takes the conformal contact into account and two-degree-of-freedom (2DOF) without considering conformal contact is established. The approximate analytical solution of the nonlinear frequency characteristics of the system at steady state is derived. By comparing with the results obtained from numerical method, the theoretical analysis process is proved to be valid. And it is found that the overall amplitude and angular displacement transmissibility of the 3DOF model are smaller than the 2DOF model, especially at resonance frequency. The effects of the friction damping ring moment inertia, stiffness of DMF, and axial friction torque on the frequency characteristics of system and angular displacement transmissibility are analyzed. The forced vibration response analysis of the 3DOF model is conducted, through which the torsional angle variations of the primary flywheel, friction damping ring, and secondary flywheel with time are obtained. The results show that the amplitude of the secondary flywheel is much smaller than that of the primary flywheel, indicating that the DMF has prominent damping performance.

NUMERICAL FREQUENCY RESPONSE ANALYSIS OF SWITCHING CONVERTERS BEHAVIORAL MODELS

2019 ◽  
Author(s):  
Aleksey Shkolin
Keyword(s):  
Time Domain ◽  
Nonlinear Dynamic ◽  
Frequency Characteristics ◽  
Response Analysis ◽  
Switching Converters ◽  
Behavioral Models ◽  
Pulse Converter ◽  
Signal Mode ◽  
The Time Domain ◽  
Simulated Object

This work is devoted to a method for numerically determining the frequency characteristics when modeling nonlinear dynamic objects, in particular during behavioral modeling of pulse converter circuits. The analysis of existing methods for modeling the frequency characteristics of pulse converters is carried out. A technique is given for reducing the amount of calculations when calculating the frequency characteristics of models of nonlinear dynamic pulse systems in the field of their stability based on a calculation in the time domain. This allows one to take into account the essential features of the studied nonlinear objects, in contrast to the linearized models applicable only to the small signal mode. The method is based on the use of correlation analysis when finding the steady-state stationary motion of the simulated object in the time domain while varying the frequency of the harmonic input signal. The results of modeling using the proposed approach are presented.

Dynamic vibratory motion analysis of a multi-degree-of-freedom torsional system with strongly stiff nonlinearities

2014 ◽  
Vol 229 (8) ◽  
pp. 1399-1414 ◽  
Author(s):  
Jong-yun Yoon ◽  
Hyeongill Lee
Keyword(s):  
Numerical Simulation ◽  
Nonlinear Dynamic ◽  
Harmonic Balance ◽  
Harmonic Balance Method ◽  
Degree Of Freedom ◽  
Balance Method ◽  
Nonlinear Frequency ◽  
Dynamic Behaviors ◽  
Resonance Frequencies ◽  
Torsional System

Physical driveline systems have inherent nonlinearities such as multiple piecewise linear springs, gear backlashes, and drag torques. The multi-staged clutch dampers, in particular, cause severe problems in simulating the nonlinear dynamic behaviors of multi-degree-of-freedom systems. In order to analyze the nonlinear dynamic behaviors of the system, the harmonic balance method has been employed. This study suggests a method to overcome the convergence problems with strong nonlinearities by employing two distinct smoothening factors for stiffness and hysteresis. First, the dynamic behaviors of the multi-degree-of-freedom torsional system are investigated by employing multi-staged clutch dampers subjected to a sinusoidal excitation. Second, the effects of system parameters are examined with respect to dynamic characteristics of torsional vibration. The regimes of resonance frequencies along with the relevant parameters of the system are investigated by calculating backbone curves, which reduce the calculation time significantly. In order to validate harmonic balance method simulation, the simulated results are compared with those of numerical simulation. Harmonic balance method is shown to be more efficient than numerical simulation in calculating the nonlinear frequency response, as well as in simulating the steady-state responses without transient response effect.

scholarly journals Simple Degree-of-Freedom Modeling of the Random Fluctuation Arising in Human–Bicycle Balance

2019 ◽  
Vol 9 (10) ◽  
pp. 2154 ◽  
Author(s):  
Katsutoshi Yoshida ◽  
Keishi Sato ◽  
Yoshikazu Yamanaka
Keyword(s):  
Angular Displacement ◽  
Degree Of Freedom ◽  
Training Data ◽  
Statistical Hypothesis ◽  
Random Fluctuation ◽  
Model Parameters ◽  
Statistical Hypothesis Testing ◽  
Measured Time ◽  
Kolmogorov Smirnov ◽  
Fluctuation Model

In this study, we propose a new simple degree-of-freedom fluctuation model that accurately reproduces the probability density functions (PDFs) of human–bicycle balance motions as simply as possible. First, we measure the time series of the roll angular displacement and velocity of human–bicycle balance motions and construct their PDFs. Next, using these PDFs as training data, we identify the model parameters by means of particle swarm optimization; in particular, we minimize the Kolmogorov–Smirnov distance between the human PDFs from the participants and the PDFs simulated by our model. The resulting PDF fitnesses were over 98.7 % for all participants, indicating that our simulated PDFs were in close agreement with human PDFs. Furthermore, the Kolmogorov–Smirnov statistical hypothesis testing was applied to the resulting human–bicycle fluctuation model, showing that the measured time responses were much better supported by our model than the Gaussian distribution.

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