A theoretical simulation for MBN testing: Modeling microscopic local magnetization jumps in magnetic domain movement

Abstract

Magnetic Barkhausen Noise (MBN) signals are adoped for the non-destructive evaluation of residual stress and plastic deformation due to their sensitivity to micro defects in material. Such MBN signals originate from discontinuous magnetization jumps accompanied by blocking of the pinning effect on the magnetic domain. This paper analyzes the influencing factors and laws of MBN non-destructive evaluation by numerically simulating discontinuous magnetization jumps. The pinning effect on the movement of the magnetic domain is considered as a random barrier field with a Gaussian distribution, and the discontinuous magnetization jumps are described as a transition in the local magnetization state. Solving Maxwell equations under varying current excitations based on the finite difference method allows simulating the magnetization evolution during non-destructive testing based on an iterative algorithm to realize MBN signal analysis. The theoretical analyses combined with existing experimental data show that the simulations can predict the influence of the excitation frequency, plastic deformation and stress level on the MBN signals, while also give explanations on some basic experimental phenomena and laws. This proposed theoretical simulation method is available to describe the mechanisms and causes of the MBN signals from a microscopic perspective for magnetic jump events.