机械结合部动态特性的等效参数研究

Equivalent Characteristic Parameters of Mechanical Joints

为提高机械结构数值分析时结合部动态特性参数的应用简便性,提出一种基于等效参数的机械结合部动态特性分析方法。在通过实验获得具有通用性的结合部单位面积上的法向动态刚度和切向动态刚度的基础上,将单位面积上的结合部等效为各向同性连续介质,基于GW接触模型建立单位面积上的结合部微观形貌和结合部动态刚度变化关系式,根据离散单元应力波传播条件研究结合部单位面积上的法向动态刚度和切向动态刚度之间内在联系,推导出结合部动态特性的等效参数-单位面积上的弹性模量和泊松比,并以螺栓连接的两钢板为对象进行数值分析,将计算结果和试验测量结果进行比较,以验证结合部动态特性等效参数的可行性和准确性,为深入研究机械结合部问题奠定基础。

To improve the simplicity of dynamic characteristic parameters of mechanical joints in numerical analyzing a mechanical structure, a new method based on the equivalent parameters is proposed. The universal normal and tangential dynamic stiffness of joints in the unit area are obtained by experiments, and the joint in the unit area is equivalent to the isotropic continuous medium. Based on the GW contact model, the relationship between the microstructure and the dynamic stiffness of the joint in the unit area is established. According to the stress wave propagation condition of discrete elements, the relationship between the normal and tangential dynamic stiffness in the unit area is studied. Equivalent characteristic parameters of joints, including the elastic modulus and Poisson’s ratio in the unit area, are deduced. Two bolted steel plates are taken as an example to be analyzed theoretically and experimentally. The comparison between results of calculation and results of experiment verifies the feasibility and accuracy of the proposed method. The result presented in this work can be considered as a stepping stone to be used toward the further research of joints’ problem.