Contact Resistance Model and Thermal Stability Analysis of Bolt Structure

This paper introduces a contact resistance model of bolt structures based on virtual material method. The main idea of the model is to interpose a virtual layer between the overlapped bus bar and define properties including equivalent resistivity and equivalent modulus of elasticity to describe the dynamic characteristics of the distributed contact resistance. The determining method of these properties is introduced, and the validity of the model is demonstrated by comparing the calculated contact resistance with the measured results. The model is further applied to the coupled electromagnetic–stress–thermal finite-element calculation to analyze the thermal stability of the bolt structure. The temperature rise process inside the bolt structure is studied, and the strengthening effect of the electrodynamic force on the thermal field is revealed. Besides, the influences of contact loosening and oxidation are also researched with the method.