机械结合面法向动态接触刚度理论模型与试验研究

机械结合面经常可能在动态条件下工作,使得结合面的接触状态偏离静态工作状态,导致接触刚度发生改变。为了揭示动态接触刚度的变化规律,考虑两个粗糙结合表面上单个微凸体由弹性变形向弹塑性变形以至最终向完全塑性变形转化的接触过程,建立一个振动周期内各变形阶段微凸体的平均接触刚度模型;在此基础上,基于高斯分布假设,建立整个粗糙结合表面的动态接触刚度解析模型。该模型揭示了接触面压、振动频率和相对位移振幅对动态接触刚度的影响规律,并与试验结果和静态接触刚度计算结果进行了比较。研究表明:法向动态接触刚度和静态接触刚度与接触面压之间的关系基本一致,但有一定偏离。这种偏离程度随动态位移幅值和振动频率的增加而分别呈线性和非线性增大。

Theoretical and Experimental Research on Normal Dynamic Contact Stiffness of Machined Joint Surfaces

Machined joint surfaces may often work under dynamic conditions, making contact state of the joint surfaces deviates from static operating one, and causing the contact stiffness to change. In order to reveal the variation of dynamic contact stiffness, The average contact stiffness modelof a vibration cycle within each deformation stageis developed based oncontact mechanics that the deformation transitions from elastic, through elastic-plastic, to eventually to the plastic, respectively. On this basis, an analytical model of the rough surface dynamic contact stiffness is developed based on the Gaussian distribution assumption. This model reveals the influence of contact pressure, vibration frequency and relative displacement amplitude on the dynamic contact stiffness, and be compared with the experimental results and the static contact stiffness. The results show that the relationship of normal dynamic contact stiffness, static contact stiffness and the contact surface pressure is roughly consistent,but there is a certain deviation. The degree of the deviation increases with dynamic displacement amplitude and frequency of vibration, respectively linearly and non-linearly.