Magneto-mechanical coupling model of ferromagnetic materials under fatigue loading and its application in metal magnetic memory method

Abstract

Fatigue damage of materials is generally evaluated by the degree of degradation of mechanical properties under fatigue loading. Existing experiments show that fatigue damage of ferromagnetic materials can also be evaluated utilizing changes in magnetization, but the quantitative relationship between magnetization changes and fatigue damage is still unclear. In this paper, a nonlinear magneto-mechanical coupling constitutive relation for ferromagnetic materials under fatigue loading is established based on the local equilibrium state of magnetization and the stress-strain response relationship in classical fatigue theory. The magnetic induction intensity of the ferromagnetic materials predicted by the present model increases with the number of cyclic loadings, and then tends to stabilize and finally increase rapidly, which is consistent with the existing experimental results. The model can also predict the evolution of complex magneto-mechanical coupling behavior under different loading times. In addition, the relationship between the evolution of spontaneous magnetic field (SMF) and fatigue damage for ferromagnetic materials is discussed in details. These results are helpful to understand the magneto-mechanical coupling behavior of ferromagnetic materials during fatigue damage process and also have important significance for the fatigue damage monitoring in practical engineering.