Study on the Judgment of Fatigue Damage Stages in Welds Based on Entropy Analysis

This study aims to explore the relationship between the weld fatigue stages and metal magnetic memory signals so as to address challenges in detecting fatigue damage. The fatigue experiments and magnetic memory testing were conducted on various types of weld. The experiment results reveal the limitations of using the original metal magnetic memory signal in the identification of the weld fatigue damage stage. To more accurately characterize the fatigue damage stage, multiple types of information entropies of metal magnetic memory signals are extracted, and the identification method based on fused information entropy is proposed. The results demonstrate that the change features of multiple types of information entropy can more accurately characterize the fatigue damage stage of weld compared with original metal magnetic memory signal. Moreover, the proposed fused information entropy contains the primary information of various entropies, resolving discrepancies in different entropy results for the same specimen, and enhances the accuracy of identification.