EXPERIMENTAL RESEARCH ON THE EFFECT OF CRACKS ON METAL MAGNETIC MEMORY SIGNALS

In order to analyze the influence of cracks in stress concentration region on metal magnetic memory signals, step-to-step loading and tensile tests were carried out on two kinds of rhomboid defect specimens of Q345 steel with and without cracks, and the metal magnetic memory signals on the surface of the specimens after unloading were collected. The residual equivalent stress distribution of the specimens after unloading was obtained by ABAQUS finite element simulation. The distribution and evolution of metal magnetic memory signals were compared and analyzed, and four characteristic parameters reflecting the distortion degree of metal magnetic memory signals were extracted. The results show that the metal magnetic memory signals can reflect the evolution process of residual stress propagation, and the distribution characteristics of the metal magnetic memory signals will change due to the existence of cracks. Quantitative analysis of the characteristic parameters of metal magnetic memory signals shows that the existence of cracks does not change the overall law of the distortion degree of the metal magnetic memory signals with the increase of applied load, but both the distortion degree of metal magnetic memory signals and its rate will increase with the increase of load.