Quantitative analysis of the relationship between non-uniform stresses and residual magnetizations under geomagnetic fields

Abstract

The quantitative relationship between non-uniform stresses and stress-induced residual magnetizations in ferromagnetic materials under geomagnetic fields was investigated. A ferromagnetic steel specimen with two symmetric notches was stretched to generate a non-uniform stress distribution. The residual leakage magnetic field and surface strain of the specimen were detected. Stress distribution was calculated according to the tested stress-strain curve of the material. The residual magnetization inside the specimen was reconstructed using residual leakage magnetic field signals. The quantitative relationship between stress and stress-induced residual magnetization was then established. Stress-induced residual magnetization was observed along the stress direction, and the intensity of the residual magnetization increased almost linearly with increasing stress.