Abstract The main aim of this work was to numerically investigate the effect of sequences of variable amplitude shear loading on contact tractions/stresses and on the development of life estimation methodologies for these more challenging loading histories. In this setting, a finite element (FE) model has been implemented in order to simulate a cylinder on plane contact problem for an aeronautical Al 7075-T651 alloy. High-Low (H-L) and Low-High (L-H) shear amplitude loading sequences under partial and gross slip conditions were considered in three different case studies. For the case studies where gross slip was involved, the proposed life estimation procedure was enhanced to include the effect of material loss due to wear. More explicitly, such procedure was based on the use of (i) the SWT (Smith-Watson-Topper) multiaxial fatigue model, (ii) the Theory of Critical Distances, (iii) Miner's cumulative damage rule and (iv) the numerical update of the contact surfaces profiles (for loading blocks under gross slip). The numerical analyses for the case studies under partial slip revealed that, when the presence of wear is neglected in the modelling, the Miner's rule provided a divergence between the expected life for the H-L and L-H loading blocks. This difference was considerably larger when gross slip took place. For the case study involving the presence of gross slip in one of the shear loading blocks, the calculated life tended to infinite when the damage generated by the high amplitude block is greater than a certain critical value. These studies are the basis for an experimental programme which will be carried out in the 4 actuators fretting fatigue rig of the University of Brasilia.

中文翻译：

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考虑局部和总滑动状态的变幅载荷下的微动疲劳：数值分析

摘要 这项工作的主要目的是数值研究变幅剪切载荷序列对接触牵引力/应力的影响，以及对这些更具挑战性的载荷历史的寿命估计方法的发展。在此设置中，已实施有限元 (FE) 模型以模拟航空 Al 7075-T651 合金的圆柱面接触问题。在三个不同的案例研究中考虑了部分和总滑动条件下的高-低 (HL) 和低-高 (LH) 剪切振幅加载序列。对于涉及总滑移的案例研究，建议的寿命估算程序得到了增强，以包括由于磨损造成的材料损失的影响。更明确地说，此类程序基于 (i) SWT (Smith-Watson-Topper) 多轴疲劳模型的使用，(ii) 临界距离理论，(iii) Miner 的累积损伤规则和 (iv) 接触面轮廓的数值更新（用于在总滑移下加载块）。部分滑动情况下案例研究的数值分析表明，当在建模中忽略磨损的存在时，Miner 规则提供了 HL 和 LH 加载块的预期寿命之间的差异。当发生粗滑时，这种差异要大得多。对于涉及其中一个剪切加载块中存在总滑移的案例研究，当高振幅块产生的损坏大于某个临界值时，计算寿命趋于无限。