Gear Rattle Modeling Based on Transient Stiffness and Damping Analysis

2012 ◽  
Vol 271-272 ◽  
pp. 936-947
Author(s):  
Ming Qin ◽  
Ning Xie ◽  
Hui Wang ◽  
Kai Zhang ◽  
Xue Ping Liu ◽  
...  
Keyword(s):  
Physical Model ◽  
Traditional Method ◽  
Relative Displacement ◽  
Simulation Program ◽  
Gear Pair ◽  
Modeling And Analysis ◽  
Gear Contact ◽  
Stiffness And Damping ◽  
Gear Rattle

Structural characters of gear contact have a determinative impact on gear rattle. Contrarily traditional method using average stiffness and damp coefficients which weakens the accuracy on modeling and analysis of gear rattle phenomenon, in this paper, a methodology modeling gear rattle process with transient stiffness and damp coefficients is proposed. Gear rattle process is modeled by considering the physical model of gear contact, gear pair movement, and actually geometrical meshing curve. A study of gear rattle is made by the simulation program and an experiment is also done to verify the method. Results show that this method can effectively analyze the frequency and the relative displacement of gear rattle, etc.

Nonlinear Isolator Optimization Using RMS Cost Function

2004 ◽  
Author(s):  
A. Narimani ◽  
M. F. Golnaraghi
Keyword(s):  
Closed Form Solution ◽  
Optimization Method ◽  
Relative Displacement ◽  
Form Solution ◽  
Jump Phenomenon ◽  
Nonlinear Parameters ◽  
Strongly Nonlinear ◽  
Damping Characteristics ◽  
Stiffness And Damping ◽  
Boundary Limits

In this paper using a modified averaging method the frequency response of a general nonlinear isolator is obtained. Stiffness and damping characteristics are considered cubic functions of displacement and velocity through the isolator. Analytical results are compared with those obtained by numerical integration in order to validate the closed form solution for strongly nonlinear isolator. While increasing the nonlinearity in the system improves the response of the isolator, stability and jump avoidance conditions set boundary limits for the parameters. The effects of nonlinear parameters to avoid jump phenomenon are discussed in detail. The set of parameters where the system behaves regularly are found and the nonlinear isolator is optimized based on RMS optimization method. Using this method the RMS function of absolute acceleration of the sprung mass is minimized versus the RMS function of relative displacement.

Characterization of Nonlinear Rattling Behavior of a Gear Pair Through a Validated Torsional Model

2021 ◽  
Author(s):  
Ata Donmez ◽  
Ahmet Kahraman
Keyword(s):  
Piecewise Linear ◽  
Nonlinear Behavior ◽  
Severity Index ◽  
System Response ◽  
Gear Pair ◽  
Computationally Efficient ◽  
Linear Solution ◽  
Set Up ◽  
The Impact ◽  
Gear Rattle

Abstract Dynamic response of a gear pair subjected to input and output torque or velocity fluctuations is examined analytically. Such motions are commonly observed in various powertrain systems and identified as gear rattle or hammering motions with severe noise and durability consequences. A reduced-order torsional model is proposed along with a computationally efficient piecewise-linear solution methodology to characterize the system response including its sensitivity to excitation parameters. Validity of the proposed model is established through comparisons of its predictions to measurements from a gear rattle experimental set-up. A wide array of nonlinear behavior is demonstrated through presentation of periodic and chaotic responses in the forms of phase plots, Poincaré maps, and bifurcation diagrams. The severity of the resultant impacts on the noise outcome is also assessed through a rattle severity index defined by using the impact velocities.

Digital Simulation of Impact Phenomenon in Spur Gear Systems

1977 ◽  
Vol 99 (3) ◽  
pp. 792-798 ◽  
Author(s):  
R. C. Azar ◽  
F. R. E. Crossley
Keyword(s):  
Simulation Model ◽  
Digital Simulation ◽  
Spur Gear ◽  
Gear Pair ◽  
Frequency Spectra ◽  
Similar Frequency ◽  
Gear Teeth ◽  
Tooth Form ◽  
Stiffness And Damping ◽  
Clearance Model

A digital simulation model is developed to represent a lightly loaded geared torsional system consisting of a drive unit, spur gear pair and load connected by flexible shafts. A clearance model called an Impact Pair [13] is used to represent the gear pair and includes the effects of backlash, time-varying stiffness and damping of the gear teeth and tooth-form error. Experimentally determined frequency spectra of the torsional oscillations of a gear-driven shaft have been plotted and reported on earlier [1]. Similar frequency plots are obtained from the simulation study, and data from these plots are compared with the experimental results for a variety of parameter changes including shaft speed, backlash and load. Results indicate that the simulation model portrays reasonably well the torsional behavior of the output shaft.

Design and Analysis of a Magnetorheological Fluid Mount Featuring Uni-Directional Squeeze Mode

2015 ◽  
Author(s):  
Xian-Xu Bai ◽  
Peng Chen ◽  
Li-Jun Qian ◽  
Ping Kan
Keyword(s):  
Dynamic Stiffness ◽  
Magnetorheological Fluid ◽  
Relative Displacement ◽  
Bottom Surface ◽  
Damping Properties ◽  
Damping Force ◽  
Equivalent Damping ◽  
Engine Vibration ◽  
Coil Winding ◽  
Stiffness And Damping

A magnetorheological fluid (MRF) mount featuring unidirectional squeeze mode for vehicle engine mounting system is proposed and designed to attenuate the engine vibration with characteristics of broadband and small amplitude. The MRF mount is comprised of upper and lower bases for installation, a main rubber for static load, a bobbin for electromagnetic coil winding and a squeeze plate. The bottom surface of the bobbin and the top surface of the squeeze plate form the polar plates, between which the MRF is squeezed during the rebound of the MRF mount. Combining dynamic stiffness property of passive hydraulic mounts without fluid and adjustable damping force of MRF at squeeze mode, the MRF mount could provide a unique variable dynamic stiffness and damping properties, by adjusting the exciting current. To evaluate the performance of the MRF mount, a mathematical model considering the behavior of MRF at squeeze mode is derived to theoretically analyze and numerically simulate the dynamic stiffness and equivalent damping properties of the MRF mount. Further, the MRF mount based quarter vehicle mounting system model considering suspension system is constructed to analyze the force transmissibility of engine mounting system in frequency domain and simulate the relative displacement response in time domain.

Computational Issues Associated With Gear Rattle Analysis: Part I — Problem Formulation

1992 ◽  
Author(s):  
C. Padmanabhan ◽  
T. E. Rook ◽  
Rajendra Singh
Keyword(s):  
Numerical Solution ◽  
Mathematical Formulation ◽  
Order Reduction ◽  
Problem Formulation ◽  
Reduction Gear ◽  
Type Problem ◽  
Contact Ratio ◽  
Processing Stage ◽  
Gear Contact ◽  
Gear Rattle

Abstract This paper proposes a new procedure for formulating the gear rattle type problem analytically before attempting a numerical solution. This step is necessary due to the nature of the mathematical formulation with vibro-impacts, which is non-analytical and hence causes numerical “stiffness”. The procedure is essentially an “intelligent” pre-processing stage and is based on our vast experience in simulating such systems. Important concepts such as order reduction, gear contact ratio, appropriate choice of non-dimensionalization parameters are illustrated through several examples.

Research on the centre distance separability of parallel shaft line gear pair

2021 ◽  
pp. 095440622110358
Author(s):  
Chao He ◽  
Yangzhi Chen ◽  
Weijia Lin ◽  
Yueling Lyu
Keyword(s):  
Theoretical Basis ◽  
Design Theory ◽  
Simulation Analysis ◽  
Design Method ◽  
Contact Spot ◽  
Gear Pair ◽  
Shaft Line ◽  
Pure Rolling ◽  
Milling Method ◽  
Gear Contact

For gear pairs with centre-distance separability, transmission ratios are not affected by centre distance error. Based on space curve meshing theory, the centre distance separability of a line gear pair was studied. A novel line gear pair called the separable and pure rolling parallel shaft line gear pair (SPRPSLG) was proposed, which has centre-distance separability characteristics and pure rolling transmission. The basic design theory of the SPRPSLG pair was established. A design method of the SPRPSLG pair with an eccentric arc tooth profile was given. An SPRPSLG pair example was designed and manufactured using the form milling method. Kinematic experiments and meshing efficiency experiments were conducted. Gear contact spot testing and gear contact simulation analysis were carried out. The SPRPSLG pair was shown to have centre distance separability, which provides a further theoretical basis for the popularization and application of line gears.

Evaluation of Contact Fatigue Life of a Wind Turbine Gear Pair Considering Residual Stress

2018 ◽  
Vol 140 (4) ◽  
Author(s):  
Heli Liu ◽  
Huaiju Liu ◽  
Caichao Zhu ◽  
Haifeng He ◽  
Peitang Wei
Keyword(s):  
Residual Stress ◽  
Fatigue Life ◽  
Stress State ◽  
Wind Turbine ◽  
Axial Stress ◽  
Contact Fatigue ◽  
Tooth Surface ◽  
Gear Pair ◽  
Contact Fatigue Life ◽  
Gear Contact

Contact fatigue is a main fatigue mode of gears such as those used in wind turbines, due to heavy duties occurring in engineering practice. The understanding of the gear contact fatigue should be based on the interaction between the local material strength and the stress state. Under the rolling–sliding motion, the multi-axial stress state makes the gear contact fatigue problem more complicated. A numerical contact model is proposed to evaluate the contact fatigue life of an intermediate parallel gear stage of a megawatt level wind turbine gearbox. The gear meshing theory is applied to calculate the geometry kinematics parameters of the gear pair. The gear contact is assumed as a plane strain contact problem without the consideration of the influence of the helical angle. The quasi-static tooth surface load distribution is assumed along the line of action. The elastic mechanics theory is used to calculate the elastic stress field generated by surface tractions. The discrete convolute, fast Fourier transformation method is applied to estimate the subsurface stresses distributions. In order to describe the time-varying multi-axial stress states during contact, the Matake, Findley, and Dang Van multi-axial fatigue criteria are used to calculate the critical planes and equivalent stresses. Both the statistic and the deterministic fatigue life models are applied by choosing the Lundberg–Palmgren (LP), Zaretsky models, respectively. The effect of the residual stress distribution on the contact fatigue initiation lives is discussed. In addition, the crack propagation lives are estimated by using the Paris theory.

Sign in / Sign up

Export Citation Format

Share Document