Fatigue Cohesive Zone-Magnetomechanical Coupling Model for Crack Initiation Detection at Coating/Substrate Interface

We develop a fatigue cohesive zone-magnetomechanical coupling model for predicting crack initiation at coating/substrate interface of ferromagnetic materials. The model is constructed based on the spontaneous magnetization phenomenon and the cohesive zone concept. The variation of measurable physical magnetic field intensity with fatigue cycles at the interfacial pre-crack tip is analyzed. The physical mechanism underlying generation and variation of interfacial spontaneous magnetization is also revealed from magnetic domain movement. The model can be used to calculate the magnetic field intensity threshold of interfacial crack initiation, which provides the evaluation guidance for magnetic nondestructive testing of coating/substrate interface.