Fretting Wear Modeling of Cylindrical Line Contact in Plane-Strain Borne by the Finite Element Method

2019 ◽  
Vol 86 (6) ◽  
Author(s):  
Huaidong Yang ◽  
Itzhak Green
Keyword(s):  
Finite Element ◽  
Plane Strain ◽  
Beam Theory ◽  
Fretting Wear ◽  
Partial Slip ◽  
Wear Volume ◽  
Element Analysis ◽  
The Finite Element Analysis ◽  
Line Contacts ◽  
Theoretical Predictions

This is the first study to develop an empirical formulation to predict fretting wear (volume removal) under frictional conditions for plane-strain line contacts as borne out by the finite element analysis (FEA). The contact is between a deformable half-cylinder rubbing against a deformable flat block. The FEA is guided by detailed physical conceptions, with results that subsequently lead to the methodical modeling of fretting wear. The materials in contact are first set to steel/steel, then to Alloy617/Alloy617, and finally to copper/copper. Various coefficients of friction (COFs) and the Archard Wear Model are applied to the interface. Initially, pure elastic conditions are investigated. The theoretical predictions for the wear volume at the end of the partial slip condition in unidirectional sliding contact agree very well with the FEA results. The empirical formulation for the initial gross slip distance is constructed, again revealing results that are in good agreement with those obtained from the FEA for different materials and for various scales. The Timoshenko beam theory and the tangential loading analysis of a half elastic space are used to approximate the deflection of the half-cylinder and the flat block, respectively. That theory supports well the empirical formulation, matching closely the corresponding FEA results. The empirical formulation of the wear volume for a general cycle under fretting motion is then established. The results are shown to be valid for different materials and various COFs when compared with the FEA results. Finally, plasticity is introduced to the model, shown to cause two phenomena, namely junction growth and larger tangential deformations. Wear is shown to either increase or decrease depending on the combined influences of these two phenomena.

Finite Element Study of the Effect of Load Sequence on the Fretting Wear

2020 ◽  
Author(s):  
Pankaj Dhaka ◽  
Raghu V. Prakash
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Fretting Wear ◽  
Element Analysis ◽  
The Finite Element Analysis ◽  
Low Load ◽  
Dimensional Finite Element ◽  
Wear Modelling ◽  
Load Sequence ◽  
Contact Parameters

Abstract Understanding the effect of load sequence is important in the context of a blade-disc dovetail joint in an aero-engine and many other such applications where, the mating surfaces undergo fretting wear under variable slip amplitude loading conditions. In the present work, a two-dimensional finite element analysis is carried out for a cylinder-on-plate configuration. The cylinder is modeled as deformable whereas the plate is modelled as rigid. An incremental wear modelling algorithm is used to model the wear of cylindrical pad while the plate is assumed as un-worn. This simulates a practical scenario where, generally one of the mating surfaces is sufficiently hardened or an interfacial harder/sacrificial element is inserted to restrict the wear to only one of the surfaces. A Fortran-based ABAQUS® subroutine UMESHMOTION is used to simulate the wear profile for the cylinder. A constant extrapolation technique is used to simulate 18000 cycles of fretting. The finite element analysis results are validated with the analytical solutions and literature data. The fretting wear modelling is carried out for two different slip amplitudes viz., 25 μm and 150 μm, to simulate the low and high slip amplitude loading respectively. Two blocks of alternate low and high slip amplitudes are applied to understand the influence of load sequence. Important contact parameters viz., contact pressure, contact stresses and contact slip are extracted. A comparison is made between the low-high and high-low load sequence based on the contact tractions and worn out profiles.

Kinetostatic Modeling of Fully Compliant Bistable Mechanisms Using Timoshenko Beam Constraint Model

2015 ◽  
Vol 137 (2) ◽  
Author(s):  
Guimin Chen ◽  
Fulei Ma
Keyword(s):  
Finite Element ◽  
Timoshenko Beam ◽  
Stable Equilibrium ◽  
Equilibrium Points ◽  
Beam Theory ◽  
Element Analysis ◽  
The Finite Element Analysis ◽  
Shear Effects ◽  
Kinetostatic Model ◽  
Constraint Model

Fully compliant bistable mechanisms (FCBMs) have numerous applications in both micro- and macroscale devices, but the nonlinearities associated with the deflections of the flexible members and the kinetostatic behaviors have made it difficult to design. Currently, the design of FCBMs relies heavily on nonlinear finite element modeling. In this paper, an analytical kinetostatic model is developed for FCBMs based on the beam constraint model (BCM) that captures the geometric nonlinearities of beam flexures that undergo relatively small deflections. An improved BCM (i.e., Timoshenko BCM (TBCM)) is derived based on the Timoshenko beam theory in order to include shear effects in the model. The results for three FCBM designs show that the kinetostatic model can successfully identify the bistable behaviors and make reasonable predictions for the locations of the unstable equilibrium points and the stable equilibrium positions. The inclusion of shear effects in the TBCM model significantly improves the prediction accuracy over the BCM model, as compared to the finite element analysis (FEA) results.

Finite element analysis of fretting wear considering variable coefficient of friction

2018 ◽  
Vol 233 (5) ◽  
pp. 758-768 ◽  
Author(s):  
Ling Li ◽  
Le Kang ◽  
Shiyun Ma ◽  
Zhiqiang Li ◽  
Xiaoguang Ruan ◽  
...  
Keyword(s):  
Finite Element ◽  
Coefficient Of Friction ◽  
Variable Coefficient ◽  
Friction Model ◽  
Slip Condition ◽  
Fretting Wear ◽  
Partial Slip ◽  
Wear Volume ◽  
The Coefficient Of Friction ◽  
Contact Surfaces

Fretting wear is a kind of material damage in contact surfaces caused by microrelative displacement between two bodies. It can change the profile of contact surfaces, resulting in loosening of fasteners or fatigue cracks. Finite element method is an effective method to simulate the evolution of fretting wear process. In most studies of fretting wear, the coefficient of friction was assumed to be constant to simplify model and reduce the difficulty of solving. However, fretting wear test showed that the coefficient of friction was a variable related to the number of fretting cycles. Therefore, this paper introduces the coefficient of friction as a function of the number of fretting cycles in numerical simulation. A wear model considering variable coefficient of friction is established by combining energy consumption model and adaptive grid technique. The nodes of contact surfaces are updated through the UMESHMOTION subroutine. The effects of constant coefficient of friction and variable coefficient of friction on fretting wear are analyzed by comparing the wear amount under different loading conditions. The results show that when compared with coefficient of friction model, fretting wear is obviously affected by variable coefficient of friction and the variable coefficient of friction model has a larger wear volume when the fretting is in partial slip condition and mixed slip condition. In gross slip condition, the difference of wear volume between variable coefficient of friction model and coefficient of friction model decreases with the increase in the displacement amplitudes.

On the finite element analysis of contacting bodies using submodelling

2005 ◽  
Vol 40 (2) ◽  
pp. 95-106 ◽  
Author(s):  
R Rajasekaran ◽  
D Nowell
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Contact Problem ◽  
Lagrange Multiplier ◽  
Analytical Approach ◽  
Partial Slip ◽  
Element Analysis ◽  
Penalty Formulation ◽  
Lagrange Formulation ◽  
The Finite Element Analysis

The implication of selecting different contact algorithms in solving a contact problem by a submodelling approach is highlighted using the example of a partial slip Cattaneo-Mindlin problem. It is shown that, by employing a penalty formulation, the state of partial slip can be incorrectly predicted as full sliding whereas a Lagrange formulation predicts the correct slip-stick behaviour. The displacements along the centre-line of contact are calculated by analytical approach and compared with finite element results. It is found that the Lagrange multiplier approach predictions match the analytical results well, but prediction by the penalty formulation is sensitive to the slip tolerance selected. It is concluded that care should be exercised while using the penalty formulation for displacement-controlled problems.

A Three-Dimensional Finite Element Damage Mechanics Model to Simulate Fretting Wear of Hertzian Line and Circular Contacts in Partial Slip Regime

2021 ◽  
pp. 1-26
Author(s):  
Arman Ahmadi ◽  
Farshid Sadeghi
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Modulus Of Elasticity ◽  
Damage Mechanics ◽  
Element Model ◽  
Operating Conditions ◽  
Fretting Wear ◽  
Partial Slip ◽  
Slip Regime ◽  
Line Contacts

Abstract In this investigation, a 3D finite element model (FEM) was developed to study fretting wear of Hertzian circular and line contacts. The wear law incorporated in this model is based on the accumulated dissipated energy (ADE). A stress-based damage mechanics finite element model using the ADE was developed to determine wear of non-conformal bodies in contact. Voronoi tessellation was used to simulate the microstructure of the materials during the fretting process. To simulate the wear area, a material removal approach was implemented in the model. The FEM was used to investigate partial slip regimes under various operating conditions. The normal and shear surface tractions for the circular and line contacts were applied to the domain in order to improve the computational efficiency. The influence of modulus of elasticity, hardness and coefficient of friction on the partial slip fretting phenomenon were studied. In order to verify the model, several fretting wear tests were conducted using AISI 8620 steel and AISI 1566 steel in partial slip regime of circular contact configuration. The properties for each material such as the modulus of elasticity, hardness, and the grain size were measured experimentally and compared with the model. For the defined load and displacement amplitude of the experimental fretting tests, both materials have shown a partial slip behavior in the initial cycles and then transition to a gross slip regime. The numerical model predicted the worn surface and wear rate in partial slip regime which corroborated well with these experimental test results.

Strength Design of a Mechanical Parking System

2014 ◽  
Vol 487 ◽  
pp. 385-388
Author(s):  
Bin Xu ◽  
Zhong Jian Yu ◽  
Yu Qing Yang ◽  
Tao Zhang
Keyword(s):  
Finite Element ◽  
Hot Spot ◽  
Beam Theory ◽  
Strength Properties ◽  
Element Analysis ◽  
Experimental Stress Analysis ◽  
The Finite Element Analysis ◽  
Parking System ◽  
Practical Engineering ◽  
Von Mises

Mechanical parking systems are widely used special electromechanical equipments. With the increasing interests on strength safety, it was becoming a hot spot to achieve its strength properties precisely. Based on Timoshenko beam theory, a mechanical parking system was simplified to a two dimensional model, and strength calculation was performed with analytical method. Furthermore, finite element method was adopted to calculate the strength properties of this mechanical parking system, and the maximum Von Mises and shear stress were approached. By comparison with experimental stress analysis, the finite element analysis was precise, which showed a potential application in practical engineering.

Simulation of Fretting Wear in Half-Plane Geometries—Part II: Analysis of the Transient Wear Problem Using Quadratic Programming

2010 ◽  
Vol 132 (2) ◽  
Author(s):  
D. Nowell
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Analytical Solution ◽  
Quadratic Programming ◽  
Fretting Wear ◽  
Hertzian Contact ◽  
Partial Slip ◽  
Finite Element Analyses ◽  
Element Analysis ◽  
Computationally Expensive

This paper presents an efficient numerical method based on quadratic programming, which may be used to analyze fretting contacts in the presence of wear. The approach provides an alternative to a full finite element analysis, and is much less computationally expensive. Results are presented for wear of a Hertzian contact under full sliding and under partial slip. These are compared with previously published finite element analyses of the same problem. Results are also obtained for the fully worn problem by allowing a large number of wear cycles to accumulate. The predicted traction distributions for this case compare well with the fully worn analytical solution presented in part one of this paper.

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