The tangential contact stiffness of joint interface is investigated in this work, using both theoretical and experimental methods. Firstly, the contact characteristics of a single asperity are analyzed on the basis of the fractal theory. Second, the total normal load and tangential stiffness of multiple asperities on the contact area are obtained by the integral over the entire surfaces. Besides, the effects of influential factors, including fractal dimension, fractal roughness, material property, friction coefficient, and load ratio, are comprehensively evaluated and discussed. Furthermore, in order to verify the effectiveness of the proposed model, two groups of test specimens are machined from different material types (45#steel and 20CrMnTi), and their actual surface profiles are measured. The structure function method is adopted to determine each profile’s fractal parameters. Under different normal load conditions, the experimental results of tangential contact stiffness on the rough surface between the upper and lower specimen are processed and obtained. By comparing the numerical results with experimental data, it is concluded that the proposed model has higher prediction accuracy on tangential contact stiffness than the comparison model. The establishment of the model not only provides a new theoretical supplement to the contact mechanics research, but also lays the foundation for the subsequent dynamic analysis of interfacial behavior on the combined structures.

这项工作采用理论和实验方法研究了接头界面的切向接触刚度。首先，基于分形理论分析了单个凹凸体的接触特性。其次，通过整个表面的积分获得接触区域上多个凹凸体的总法向载荷和切向刚度。此外，还综合评价和讨论了分形维数、分形粗糙度、材料性能、摩擦系数、载荷比等影响因素的影响。此外，为了验证所提出模型的有效性，采用不同材料类型（45#钢和20CrMnTi）加工了两组试件，并测量了它们的实际表面轮廓。采用结构函数法确定各剖面的分形参数。处理并得到不同法向载荷条件下上下试件粗糙表面切向接触刚度的实验结果。通过将数值结果与实验数据进行比较，得出结论：所提模型比对比模型具有更高的切向接触刚度预测精度。模型的建立不仅为接触力学研究提供了新的理论补充，也为后续组合结构界面行为的动态分析奠定了基础。