Research on contact stiffness characteristics of deterministic rough surface based on finite element APDL method

Studying the joint surface characteristic parameters has far-reaching theoretical and practical significance for improving the manufacturing quality of the equipment. In this paper, the statistical method is used to characterize the parameters of the deterministic rough surface of 20 Cr and HT300 materials, and the height and roughness of the rough surface along the turning direction and the vertical turning direction are calculated, respectively. The results show that the distribution of rough surfaces follows the law of normal distribution. The Ra value along the turning direction is about 0.294μm, and the Ra value perpendicular to the turning direction is about 0.551μm. The roughness perpendicular to the turning direction is greater than that in the turning direction. The normal contact stiffness parameters of two kinds of rough surfaces are modelled by using finite element APDL technology and different contact strategies. The method is: (1) a rigid plane and a rough plane contact, (2) two rough surfaces contact normal stiffness. The calculation shows that the contact stiffness and the directional contact load of the joint surface obey the exponential distribution. The contact stiffness calculated by Method (2) is smaller than that calculated by Method (1), and the contact stiffness of the joint surface is closer to the experimental value.