复杂交变载荷下的微动运行机制影响因素分析

Analysis of the factors influencing the fretting operation mechanism under complex alternating loads

微动问题是导致机械连接结构失效的主要因素之一,目前大多数研究都在恒定法向接触载荷工况下开展。而许多实际工程问题中,存在着可变法向载荷和轴向载荷的多轴加载工况,致使微动运行机制的研究结果无法很好地解释多轴加载工况下的微动行为。为此,对复杂交变载荷下的微动运行机制影响因素进行了分析,以期为双轴加载工况下的微动失效行为提供有力的分析方法。首先,在传统微动疲劳模型的基础上,分析了受循环交变法向载荷和轴向载荷共同作用下的微动摩擦学行为和动力学特征,提出了一种Q-P曲线分析方法;然后,推导了双轴交变载荷参数与微动运行状态之间的函数表达式;最后,讨论了不同的加载参数(法向载荷的均值P m、法向载荷的幅值P a、远端载荷的均值F B,m、远端载荷的幅值F B,a、双轴加载相位差φ和刚度比R sti)对Q-P曲线形状和位置的影响。研究结果表明:比例加载情况下,Q-P曲线为直线函数;非比例加载情况下,Q-P曲线为椭圆函数;加载参数会影响Q-P曲线的形状和位置。Q-P曲线分析方法为复杂交变载荷作用下的微动失效分析提供了有效的表征方法。

The fretting problem is one of the main factors that cause the failure of mechanical connection structures.Most studies are currently conducted under constant normal contact load conditions.However,in many practical engineering problems,the multi-axis loading conditions with variable normal load and axial load widely exist and lead to the fact that the current research results on the fretting motion operation mechanism can not well explain the fretting behavior under multi-axis loading conditions.Therefore,firstly based on the traditional fretting fatigue model,the micro-oscillation behavior and dynamic characteristics under the combined action of cyclic alternating normal load and axial load were analyzed,and a Q-P curve analysis method was proposed.Secondly,the functional expression between the biaxial alternating load parameters and the micro-motion operating state was derived.Finally,the effects of different loading parameters(mean value of normal load P m,amplitude of normal load P a,mean value of bulk load F B,m,amplitude of bulk load F B,a,phase differenceφof biaxial loading and stiffness ratio R sti)on the shape and position of Q-P curves were discussed separately.The research results show that the Q-P curve is a linear function under proportional loading and an elliptical function under non-proportional loading.The loading parameters affect the shape and position of the Q-P curve.The Q-P curve analysis method provides an effective characterization method for micro-motion failure analysis under complex alternating loads.