Identification of Joint Surface Stiffness Considering the Theory of Bolt Elastic Interaction and Comparative Analysis of Multiple Modeling Methods

The changes in stiffness and damping of the bolted joint surface may lead to variations in the dynamic properties of the overall bolted connection structure. Therefore, accurately determining the dynamic parameters of the joint surface holds significant practical importance in engineering. This paper focuses on a matrix distributed bolt connection structure and develops a bolt elastic interaction model to examine the changes in bolt pre-tension. The stiffness parameters of the bolt connection joint surface were identified by utilizing a genetic algorithm, taking into account the variation in bolt pre-tightening force. This identification process involved a combination of experiments and finite element analysis. The analysis focus on the disparity between the outcomes of recognition and the results derived from theoretical calculations. The research proposed an improved model that accounts for the non-uniform distribution of joint surface stiffness across varying levels of bolt pre-tightening force. Additionally, the paper examined the impact of various joint surface and bolt modeling techniques on the precision of identifying joint surface stiffness parameters. This study aimed to develop joint surface models for bolted connection structures through various equivalent modeling techniques. Subsequently, finite element modal simulations was performed, and the obtained results were compared alongside error analysis. The results suggested that taking into account the variations in bolt pre-tension resulting from the elastic interaction among bolts and the non-uniform distribution of stiffness on joint surfaces within the bolt pre-tension range can significantly improve the accuracy of equivalent modeling for bolted connection structures.