Finite element analysis of fretting wear considering variable coefficient of friction

Abstract

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.

A review of recent advances in tribology

“…Similar approach has been applied for simulating other types of wear, such as fretting and erosion. For fretting wear, the FEM-based model has been employed to calculated deflection and stress distribution, and the material removal of the solids is estimated by the Archard-type equations, but unlike the sliding wear, the geometry of worn surface due to fretting are updated every N-cycle to accelerate calculation [654]. To address the effects of accumulation and abrasion of wear debris, wear particles accumulated between rubbing solids have been modeled as a third body in the form of a thin-continuum layer [655].…”

Fretting study of an impregnated graphite bearing/nitrided stainless steel in a dry contact submitted to severe thermal-vibratory loading

“…Hence, the contribution of antimony allows an improvement in the tribological performances of the graphite at high temperatures. 24,33,34 To confirm these results, complementary tests have been carried out with only oscillatory movement (i.e. without the (T1) and (T2) vibration motions of the bearing).…”

“…Hence, the contribution of antimony allows an improvement in the tribological performances of the graphite at high temperatures. 24,33,34…”

Ti-6Al-4V fretting wear and a quantitative indicator for fretting regime evaluation

“…When the fretting run in the mix regime, more slip could be found in the initial stage, and after some cycles, slip displacement became less. 20,25,34 As a result, fretting loops would become “slimmer” (Figure 2, 20–30 N; Figure 3, 30–50 N; Figure 4, 40–80 N), and the friction force (as well as Fx/Fz) would increase.

Figure 3.3-D fretting loops under the applied displacement of 30 µm.

Figure 7.Evolutions of the coefficient of friction/traction under the loads from 15 to 100 N with the applied displacements of (a) 20, (b) 30, and (c) 40 µm.

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