Effect of preload distribution on dynamic characteristics of machine tool bolted joint structure

Abstract The bolted joint is the machine tool’s primary connection mode. The bolted joint structures have a profound influence on the dynamic performance of the machine tool. Due to factors such as design and manufacturing processes, bolted joint structures often exhibit uneven stress distribution, which severely affects the dynamic properties of the structure. The common frame connection structure in the machine tool infrastructure is used as the research object. A simulation model was established to study the influence of bolt preload distribution on structural dynamics based on the improved thin-layer element method. The results show that using more small bolts can improve the uniformity of stiffness distribution and the natural frequency of the structure. When the bolt specification and number remain unchanged, the dispersion of bolt preload has little influence on the dynamic performance of the structure. The research results have a certain guiding significance for the optimization design of bolt joint structure of machine tools.