Abstract: A force-magnetic coupling model of Q235 steel under static load tension and a low cycle fatigue life model are established to study the relationship between stress and magnetoacoustic emission (MAE) and the relationship between magnetoacoustic emission and fatigue state of ferromagnetic metal materials. From the perspective of finite element simulation, the generating mechanism of magnetoacoustic emission signals under static load tension is analyzed. According to the simulated results, the low cycle fatigue test of MAE is designed, and a self-built test platform is used to verify the proposed models. The law of magnetoacoustic emission signals under static load tension and low cycle fatigue was studied. The experimental results show that the permeability shows a linear increasing trend with the increase in the tensile stress in the elastic range under static tension, which leads to the increase in the loss on the specimen and the weakening of MAE signal. The root mean square voltage and envelope area of magnetoacoustic emission signal show a downward trend. However, during low cycle fatigue, the low cycle fatigue life of Q235 steel can be predicted by Smith-Watson-Topper model, and the amplitude and pulse counting characteristic parameters of Q235 steel decrease with the increase in cycle number. The obtained results clarify the influence of stress on MAE and fatigue state on MAE.

Key words: Q235steel, magnetoacousticemission, ferromagneticmetalmaterial, statictension, lowcyclefatigue, finiteelement