scholarly journals Research on effect of damping variation on vibration response of defective bearings

2019 ◽  
Vol 11 (3) ◽  
pp. 168781401982773 ◽  
Author(s):  
Fanzhao Kong ◽  
Wentao Huang ◽  
Yunchuan Jiang ◽  
Weijie Wang ◽  
Xuezeng Zhao
Keyword(s):  
Dynamic Model ◽  
Vibration Signal ◽  
Vibration Response ◽  
Hertzian Contact ◽  
Contact Theory ◽  
Viscous Damping ◽  
Lubricating Grease ◽  
Rolling Element ◽  
Different Types ◽  
Hertzian Contact Theory

This article presents a dynamic model of ball bearings with a localised defect on the outer raceway to analyse the effect of damping variation on the vibration response of defective bearings. First, a dynamic model is built based on the Hertzian contact theory, the interaction between the bearing inner ring, outer ring, and rolling element; the effect of damping and stiffness is considered; and the vibration equation of the bearing system is solved by the fourth-order Runge–Kutta algorithm. Then, the damping ratios of the experimental bearings using different types of viscosity lubricating grease are measured and compared with the damping ratios of the dynamic model; in addition, the viscous damping coefficient of the experimental bearings are calculated. Finally, the numerical analysis and experimental results show that the grease with a different level of viscosity affects the vibration signal of the defective bearing.

Approximate Analytical Model for Hertzian Elliptical Wheel/Rail or Wheel/Crossing Contact Problems

2008 ◽  
Vol 130 (4) ◽  
Author(s):  
F. D. Fischer ◽  
M. Wiest
Keyword(s):  
Contact Pressure ◽  
Contact Problems ◽  
Hertzian Contact ◽  
Contact Theory ◽  
Technical Accuracy ◽  
Elliptical Contact ◽  
Current Approximation ◽  
Analytical Expressions ◽  
Maximum Contact ◽  
Hertzian Contact Theory

The Hertzian contact theory is approximated according to a concept by Tanaka (2001, “A New Calculation Method of Hertz Elliptical Contact Pressure,” ASME J. Tribol., 123, pp. 887–889) yielding simple analytical expressions for the elliptical semi-axes, the maximum contact pressure, the mutual approach and the contact spring constant. Several configurations are compared using the exact Hertz theory and the current approximation. The results agree within technical accuracy.

Simulation of Traction Drive Ratio Changes

2000 ◽  
Author(s):  
Z. Zou ◽  
Y. Zhang ◽  
X. Zhang ◽  
W. Tobler
Keyword(s):  
Hertzian Contact ◽  
Contact Theory ◽  
Hydrodynamic Theory ◽  
Traction Drive ◽  
Input And Output ◽  
Piston Displacement ◽  
Simulation Results ◽  
Traction Drives ◽  
Stability And Accuracy ◽  
Hertzian Contact Theory

Abstract In the simulation model presented in this paper, the kinematic characteristics of traction drives are formulated using classical Hertzian contact theory and elasto-hydrodynamic theory. The roller swing motion is governed by an equation derived based on Newton’s Second Law and is coupled to the side slip, torque input and output, as well as ratio variations. A control strategy with feedbacks for both the roller swing and the piston displacement is applied for ratio control based on stability and responsiveness considerations. The model has been implemented systematically in Matlab/Simulink environment. The effectiveness of the ratio control system in terms of stability and accuracy is illustrated by the simulation results included in this paper.

Difference between the ideal and combined spherical joints and its effects on parallel manipulators

2019 ◽  
Vol 234 (5) ◽  
pp. 1112-1129
Author(s):  
Shuai Fan ◽  
Shouwen Fan
Keyword(s):  
Machine Tools ◽  
Parallel Manipulators ◽  
Hertzian Contact ◽  
Contact Theory ◽  
Contact Deformation ◽  
Spherical Joint ◽  
Universal Joint ◽  
Deformation Models ◽  
Hertzian Contact Theory ◽  
The Ideal

When using parallel manipulators as machine tools, the spherical joint has been widely used and replaced by a combination of a universal joint and a rotating unit, but the introduced differences and effects have not been studied in detail. In this paper, an approach to establish the mathematical models of the ideal and combined spherical joints is presented, and the differences between the two spherical joints are given from the perspective of constraints, workspace, clearance, and contact deformation. First, the non-interference workspace of a class universal joint is investigated by using a simple and clear projection method, where the constraint domain and workspace of two spherical joints are proposed. Next, the approximate clearance models of these two spherical joints are analyzed, and the corresponding contact deformation models are also given based on the Hertzian Contact theory. Finally, a 1PU + 3UPS parallel manipulator is used to verify the discrepant effects of two spherical joints on parallel manipulators. If the combined spherical joint is used, the results indicate that the improvement in the workspace is significant, but the drop in stiffness is also evident. Thus, this paper provides a theoretical basis for researchers to use combined spherical joints.

Rolling Element Bearings Fault Identification in Rotating Machines, Existing Methods of Vibration Signal Processing Techniques and Practical Considerations

2013 ◽  
Vol 430 ◽  
pp. 70-77
Author(s):  
Ninoslav Zuber ◽  
Dragan Cvetkovic
Keyword(s):  
Real Life ◽  
Vibration Signal ◽  
Vibration Monitoring ◽  
Universal Method ◽  
Bearing Failures ◽  
Rolling Element ◽  
Different Types ◽  
Processing Techniques ◽  
Failure Monitoring ◽  
Signal Processing Techniques

This paper addresses the suitability of vibration monitoring and analysis techniques to detect different types of defects in roller element bearings. Processing techniques are demonstrated on signals acquired from the test rig with defective bearings. As a result it is shown that there is no reliable universal method for bearing failure monitoring from its early occurence up to bearings failure. Two real life case studies with different types of bearing failures are presented with practical considerations on methods used for failure identification.

A Systematic Model for the Analysis of Contact, Side Slip and Traction of Toroidal Drives

1999 ◽  
Vol 122 (4) ◽  
pp. 523-528 ◽  
Author(s):  
Y. Zhang ◽  
X. Zhang ◽  
W. Tobler
Keyword(s):  
Traction Force ◽  
Hertzian Contact ◽  
Contact Theory ◽  
Kinematic Parameters ◽  
Traction Drive ◽  
Continuously Variable Transmissions ◽  
Toroidal Traction ◽  
Hertzian Contact Theory ◽  
Slip Force ◽  
Ratio Range

This paper presents a systematic model for the design and analysis of toroidal traction drive continuously variable transmissions (CVT). The contacts between the input disk, the roller and the output disk of the traction drive are formulated using the classical Hertzian contact theory. The traction force and side slip force occurring in CVT operation are modelled based on the elasto-hydrodynammic theory and are correlated to the traction drive geometric and kinematic parameters. The model allows for the quantitative analysis of traction drive operation under various torque inputs and over the desired ratio range. [S1050-0472(00)01004-7]

Extension of Hertzian Theory for Bodies With a Single Coating

2003 ◽  
Author(s):  
Shuangbiao Liu ◽  
Qian Wang
Keyword(s):  
Numerical Solutions ◽  
Layered Materials ◽  
Sufficient Accuracy ◽  
Hertzian Contact ◽  
Contact Theory ◽  
Numerical Analyses ◽  
Convenient Tool ◽  
Homogeneous Materials ◽  
Hertzian Contact Theory ◽  
Single Coating

The Hertzian theory is a convenient tool for analyzing counterformal bodies in mechanical contacts. However, it is limited to homogeneous materials. This paper reports the results from recent research that extends the Hertzian contact theory to layered materials. Numerical analyses are conducted to evaluate the accuracy of the formulas of the extended Hertzian theory, and the comparison with numerical solutions indicates that the formulas have sufficient accuracy.

scholarly journals Dynamic Model of Planetary Roller Screw Mechanism with Considering Torsional Degree of Freedom

2020 ◽  
Vol 306 ◽  
pp. 01003
Author(s):  
Linping Wu ◽  
Shangjun Ma ◽  
Qi Wan ◽  
Geng Liu
Keyword(s):  
Dynamic Model ◽  
Mechanical Design ◽  
Relative Displacement ◽  
Hertzian Contact ◽  
Torsional Stiffness ◽  
Roller Screw ◽  
Mode Characteristics ◽  
Screw Mechanism ◽  
The Relationship ◽  
Hertzian Contact Theory

To predict accurately the dynamics performance of planetary roller screw mechanism, it is necessary to establish its streamline and engineering-compliant dynamic model, which is the basis of mechanical design and precision control of the system. In this paper, the relative displacement between roller and ring gear along the line of action is deduced and the relationship between nature frequencies and the number of rollers is discussed. Considering the torsional stiffness of all components and the thread mesh stiffness based on the Hertzian contact theory, the purely torsional model for planetary roller screw mechanism is presented to reveal the natural frequencies and vibration mode characteristics of the system. The results show that the natural properties of undamped system in planetary roller screw mechanism are mainly reflected by two typical vibration modes: rotational mode and roller mode.

Reinvestigation into railway wheel-track interaction and suspension damage

2020 ◽  
pp. 095440972093202
Author(s):  
Renfan Luo ◽  
David Vincent
Keyword(s):  
High Speed ◽  
Sensitivity Study ◽  
Hertzian Contact ◽  
Contact Theory ◽  
Fe Model ◽  
Fe Modelling ◽  
Wheel Flat ◽  
The Impact ◽  
Hertzian Contact Theory ◽  
Wheel Track

Without considering either velocity or acceleration effects, the current conventional method presented in literature applies the vertical deflection of a wheel centre caused by a flat defect to the Hertzian contact theory. This method has been numerically and theoretically proved to be inappropriate and can incorrectly predict a higher wheel-rail impact force for a low speed than a high speed. Therefore, under a hypothesis of no wheel bouncing and sliding, two new methods, the velocity-based and the acceleration-based have been proposed. The former method takes the wheel centre deflection change in each computational increment from the Hertzian contact theory while the latter applies the wheel centre acceleration caused by the flat in revolutions to the wheel as a force in dynamic simulation, which interprets the speed effects on impacts precisely. A sensitivity study proves that the velocity-based method is unreliable as opposed to the acceleration-based method. A beam/rigid FE model has also been developed to inspect the wheel-track interaction by performing dynamic analysis in the time domain. It has been found out that the impact responses predicted by the FE analysis and the velocity method are similar and the FE results heavily depend on the compute increment, which implies the FE modelling in ABAQUS may be unreliable for this issue with current applied increments. Finally, the results calculated using the acceleration method have been employed to study the suspension/damper torsional stress caused by a wheel flat. This indicates that a wheel flat may lead to potential fatigue damage if without proper maintenance management.

Impact of Flexible Bent Beam Using Component Mode Techniques

1999 ◽  
Author(s):  
Cristian I. Diaconescu ◽  
Dan B. Marghitu
Keyword(s):  
Power Series ◽  
Elastic Beam ◽  
Point Of View ◽  
Component Mode Synthesis ◽  
Hertzian Contact ◽  
Contact Theory ◽  
Rigid Surface ◽  
Plastic Indentation ◽  
The Impact ◽  
Hertzian Contact Theory

Abstract The Component Mode Synthesis technique is applied to the impact of a flexible curved bar. The mode functions are selected such that the method can be made computationally as simple as possible, without compromising accuracy. From this point of view, a simple power series is selected. Both transversal and axial elastic deflection are considered. To describe the impact between the elastic beam and the rigid surface the classical Hertzian contact theory and elastio-plastic indentation theory are used.

Nonlinear Dynamic Modeling and Vibration Analysis of Faulty Rolling Bearing Based on Collision Impact

2021 ◽  
Vol 16 (6) ◽  
Author(s):  
Longkui Zheng ◽  
Yang Xiang ◽  
Chenxing Sheng
Keyword(s):  
Kinetic Energy ◽  
Potential Energy ◽  
Dynamic Model ◽  
Nonlinear Dynamic ◽  
Rolling Bearing ◽  
Hertzian Contact ◽  
Nonlinear Dynamic Model ◽  
Impact System ◽  
Rolling Element ◽  
The Impact

Abstract This study proposes a new nonlinear dynamic model of rolling bearing faults based on a collision impact system. The dynamic model accounts for the collision impact system consisting of the rolling elements and localized faults according to the nonlinear Hertzian contact. First, considering the impact of the rolling element and fault structure, the collision impact system between rolling element and localized fault is established, and the vibration responses of the collision impact system can be obtained. Second, the overall rolling bearing is treated as a mass-spring model, and the contact between the rolling element and raceway is treated as a nonlinear spring that conforms to the Hertzian contact deformation theory. Third, according to the Lagrange equation, overall potential energy, overall kinetic energy, elastic potential energy, and kinetic energy of the collision impact system are used to describe the vibration characteristics. Considering the impact of collision impact systems, a nonlinear dynamic model of rolling bearing faults is established. The simulated acceleration results based on the nonlinear dynamic model are compared to experimental results. The comparison indicates that the numerical model can be used to predict the vibration characteristics of rolling bearings faults effectively.

Sign in / Sign up

Export Citation Format

Share Document