Magnetic measurement during tensile testing of ferromagnetic materials and force-magnetic dual-variable characterization of damage

With the growing demand for safety assessment of engineering structures in modern industry, the importance of non-destructive testing technology for damage evaluation in ferromagnetic materials has become increasingly prominent. This study focuses on Q235 steel as the research subject. An integrated experimental platform was established, combining tensile testing with Magnetic Barkhausen Noise (MBN) measurement technology to systematically investigate the evolution of magnetic hysteresis loop parameters during different deformation stages and their correlation with material damage. The experiment employed a stepwise loading strategy to synchronously acquire mechanical and magnetic signal data, with key parameters such as coercivity (Hc) extracted using the integral curve method. Results demonstrate that Hc exhibits linear growth during the elastic stage, while showing a nonlinear increasing trend in the plastic stage due to dislocation pinning effects. Based on the stress-strain relationship and magnetic property variations, a force-magnetic dual-variable damage model was developed, achieving a quantitative assessment of material damage through coercivity measurements. This research provides novel theoretical foundations and technical approaches for non-destructive testing of ferromagnetic materials, demonstrating significant engineering application value.