基于表面粗糙度的铝合金材料疲劳寿命预测

Fatigue Life Prediction of Aluminum Alloy Materials based on Surface Roughness

为了研究表面粗糙度对铝合金材料疲劳寿命的影响,提出一种利用基于表面粗糙度曲线的插值法构造试件真实表面形貌的方法。首先对试件进行打磨处理,然后利用粗糙度仪提取打磨后试件的粗糙表面轮廓曲线;使用插值法重构三维有限元模型并进行疲劳寿命分析;将得到的疲劳寿命与MTS疲劳试验得到的结果相对比;最后建立了粗糙度参数与疲劳寿命之间的函数关系。结果表明:使用插值法得到的仿真疲劳寿命与试验得到的疲劳寿命结果基本一致,最大误差为19.2%,证明了该方法的正确性。粗糙度参数与疲劳寿命存在幂函数关系,基于粗糙度参数可开展疲劳寿命预测。

In order to study the effect of surface roughness on the fatigue life of aluminum alloy materials, this paper proposes a method to construct real surface morphology of the test piece based on the interpolation method of the surface roughness curve. Firstly, the test piece is polished, and then the rough surface profile curve of the polished test piece is extracted with a roughness meter. Interpolation is used to reconstruct a three-dimensional finite element model and perform fatigue life analysis. Obtained fatigue life is compared with the results obtained from the MTS fatigue test. Finally, the functional relationship between roughness parameters and fatigue life is established. Results show that the simulated fatigue life obtained by the interpolation method is basically consistent with the fatigue life results obtained by the test.The maximum error is 19.2%, which proves the correctness of the method. There is a power function relationship between roughness parameters and fatigue life, and fatigue life prediction can be carried out based on roughness parameters.