Frequency response consistency metrics for assembled structures and application to bolted joints

Assembly consistency problems affect mechanical work performance. In order to solve the assembly evaluation problem, this paper proposes a new method for evaluating the consistency of frequency response functions. Built upon the core idea of the zero-crossing method, the proposed approach addresses lateral differences and adopts an exponential function to map the differences in frequency response curves into the interval [0, 1]. A higher similarity function value closer to 1 indicates that the two frequency response curves are more similar. The recognition effect of the similarity function is verified through simulation. Based on this method, the assembly quality issues are studied using the bolted connection structure as an example. The influence of bolt tightening torque and excitation force on response consistency is investigated. The similarity of different personnel and different torque tightening sequences is measured experimentally under the condition of specified tightening torque. The experiments show that the proposed method has a significant detection effect.