交变双轴加载下钛合金微动磨损的仿真及试验研究

Simulation and experimental study of titanium alloy fretting wear under alternating biaxial loading

微动磨损是导致机械连接结构失效的主要形式之一。目前大多数研究都在恒定法向接触载荷工况下开展。然而实际工程中,广泛存在着可变法向载荷和轴向载荷的多轴加载工况,导致目前恒定法向载荷下微动磨损的研究结果不能很好地解释多轴交变加载工况下的微动磨损行为。因此,以钛合金的微动磨损为例,进行了交变双轴加载下微动磨损的仿真分析和试验测试研究。首先,建立了受循环交变双轴加载作用下的微动磨损模型;然后,对不同法向载荷幅值、位移载荷幅值、双轴加载相位差下的微动磨损行为进行了仿真,并根据Q-P曲线分析方法对这些复杂微动情况下的微动磨损机制进行了讨论;最后,在双轴加载的微动磨损试验机上进行了双轴微动磨损试验,验证了该有限元模型磨损形貌的合理性。研究结果表明:交变法向载荷的磨损形貌不同于恒定法向载荷的磨损形貌,交变下法向载荷均值与恒定法向载荷保持不变,交变法向载荷下的磨损深度及宽度均大于恒定法向载荷下的磨损深度及宽度。位移幅值和相位差一定,随着法向载荷幅值的增大,磨损宽度和深度均增加,磨损形貌由“W”型转变为“W+V”型;法向载荷幅值和相位差一定,磨损宽度和深度均随位移幅值的增大而增大;法向载荷幅值和位移幅值一定,改变双轴加载相位差,0°相位差最大磨损深度出现在接触后缘,180°相位差最大磨损深度出现在接触前缘,90°和270°相位差的前、后缘磨损深度极大值接近。

Fretting wear is one of the main forms of failure of mechanically connected structures.Most of the current studies are based on constant normal contact loading conditions.However,in actual engineering,there are widely existing multiaxial loading conditions with variable normal load and axial load,which leads to the fact that the results of the current research on fretting wear under constant normal load cannot explain the fretting wear behavior under multiaxial alternating loading conditions.Therefore,taking the fretting wear of titanium alloy as an example,simulation analysis and experimental test study of fretting wear under variable biaxial loading was carried out.Firstly,a fretting wear model subjected to cyclic alternating biaxial loading was established.Then,the fretting wear behaviors were simulated under different normal load amplitudes,displacement load amplitudes,and phase differences of biaxial loading.Based on the Q-P curve analysis method,the fretting wear mechanisms under these complex micromotion cases were discussed.Finally,the biaxial fretting wear test was carried out on a biaxial fretting wear tester,which verified the rationality of the wear morphology of the finite element model.The research results show that the wear scar of the variable normal load is different from that of the constant normal load,the mean value of the normal load under the variable load remains the same as the value of the constant normal load,the wear depth and width under the variable normal load are larger than those under the constant normal load.For a certain displacement amplitude and phase difference,the wear width and depth increase with the increase of normal load amplitude,and the wear scar changes from"W"to"W+V".For a certain normal load amplitude and phase difference,the wear width and depth increase with the increase of displacement amplitude.For a certain normal load amplitude and displacement amplitude,when the biaxial loading phase difference changes,the maximum wear depth of 0°phase difference occurs in the contact trailing edge,the maximum wear depth of 180°phase difference occurs in the contact leading edge,and the wear depth of the leading and trailing edges of the 90°and 270°phase difference are close to each other in the extreme value.