Numerical simulation of the effect of surface microgeometry and residual stress on conformal contact fretting fatigue crack initiation behavior

Abstract

Conformal contact is a commonly presented contact form in assemblies. Nonproportional loading is the main characteristics of conformal contact, which leads to prominent difficulty in revealing fretting crack behavior. In this paper, a finite element prediction model for Ti-6Al-4V pin-hole contact fretting fatigue crack initiation was developed, which simultaneously considered the effect of fretting wear, surface roughness, surface skewness, surface kurtosis, and residual stress. The results show that phase differences of stress component, change in direction of principal stress, and high stress gradient are the main reasons for the initiation of fretting fatigue under conformal contact condition. The model based on the Fatemi-Socie (FS) parameter successfully predicted the location, orientation, and fatigue life of crack initiation, which agrees well with the experimental results. Additionally, machining-induced residual stress can effectively inhibit mode I crack initiation at valleys. Moreover, ignoring the surface microgeometry characteristics reduces the prediction accuracy of the crack behavior.

A crystal plastic finite element model for the effect of surface integrity on multiaxial fatigue life after multistage machining processes

“…Maz anov a et al 10 revealed that microstructure also has a significant impact on the multiaxial fatigue behavior of materials. Our previous works [11][12][13] correlated surface roughness parameters such as skewness, kurtosis, and texture direction with fatigue life. These studies indicate that surface integrity, including residual stress, microstructure, and surface roughness, has a significant influence on the surface fatigue performance of materials.…”

Smith–Watson–Topper Parameter in Partial Slip Bimodal Oscillations of Axisymmetric Elastic Contacts of Similar Materials: Influence of Load Protocol and Profile Geometry

“…With respect to the loading protocol, the influences of out-of-phase loading [10] and phase difference ( [11,12]) (however, mainly with focus on a phase difference between bulk stresses and contact loads), as well as more complex cyclic loading paths ( [13,14]), were studied. On the other hand, regarding the influence of the surface geometry on crack initiation, the overall contact geometry ( [15,16]) and macroscopically worn profiles [17], as well as the surface microgeometry [18], surface pit treatment [19] and machined surface texture [20] have been considered. Most of the aforementioned numerical studies are based on the Finite-Element Method (FEM); while the FEM, due to its flexibility with respect to the physical modeling, can account for a wide variety of mechanisms and phenomena in a specific fretting contact-and thus achieves good predictive power under sufficiently well-defined circumstances-its demands for computational power and calculation time often make large parameter studies for the comprehensive analysis of different influencing factors unfeasible.…”