Prediction of contact stiffness in bolted interface with natural frequency experiment and FE analysis

Bolted joints are widely used when joining parts together and their dynamics is significantly influenced by bolt preload and interface roughness. In this paper, experimental test of bolted joint is implemented to explore the influence of bolt preload on the first 6 order natural frequencies, whose results reveal a phenomenon of natural frequencies increase along with bolt preload. Thin layer elements (TLE) is implemented into the finite element (FE) model to represent interface contact stiffness, and FE analysis reproduces the experimental phenomenon by changing stiffness of thin layer. By comparing the experimental test and the FE analysis, the regularity of the contact stiffness in bolted interface changes with bolt preload is obtained.