The magneto-elastoplastic coupling effect on the magnetic flux leakage signal

•The magneto-elastoplastic multi-field coupling phenomena is studied.•The experimental progress on magnetic flux leakage signal is introduced.•The new theoretical model explains the magneto-elastoplastic coupling effect.•The magnetic dipole theory explains the nonlinear signal of broken specimen. This paper introduces an experimental progress of the magneto-elastoplastic coupling phenomenon on magnetic flux leakage signal for ferromagnetic materials. The magnetic flux leakage signal on the surface of medium carbon steel was measured under the combined action of elastic load and plastic deformation. Based on the experimental results, the influences of elastic load and plastic deformation on the magnetic flux leakage signal and their coupling effects were analyzed. A theoretical mechanism of experimental phenomena was explained by the magneto-elastoplastic coupling model and magnetic charge model. The results show that the magnetic flux leakage signal increases with the increase of the elastic load, and the magnetic flux leakage signal increases first and then decreases with the increase of plastic deformation. As the elastic load increases, the effect of plastic deformation on the magnetic flux leakage signal gradually increases. The work in this paper provides a vigorous support for the safety evaluation of engineering structures caused by the combination of plastic deformation and residual stress through magnetic flux leakage signal.