Contact parameters evolution of bolted joint interface under transversal random vibrations

Bolt connection plays an important role in assembly structures. Under long-term vibrations, bolted joint interface will change due to fretting-induced friction and wear behavior. This leads to changes in the dynamic characteristics of assembly structures, which increases the difficulty of control of the structure. In this paper, a new random fretting test method was developed to reproduce realistic vibration situations as much as possible and to study the evolution of contact parameters (friction coefficient and contact stiffness) of bolted joint interfaces with increasing wear. A recently developed test rig was used to perform the fretting wear tests under random oscillation. During the tests, interface hysteresis response and bolt preload were recorded. A model-based parameter estimation method was developed to estimate the friction coefficient and tangential contact stiffness. The evolution curves of contact parameters were obtained, and the effects of initial bolt preload, excitation level, and surface roughness were discussed. To the authors' knowledge, no studies on the fretting behavior of bolted joint interfaces under random vibration have been published. This research can promote a better understanding of the fretting wear behavior of bolted joints and provide a basis for the dynamic analysis of joint-dominated structures.