Theoretical research and model study of rotating magnetic field stress measurement under uniaxial stress

To overcome the limitation of probe rotation inherent in existing magnetoelastic-based stress evaluation methods, this study proposes a novel rotating magnetic field stress measurement (RFSM) technique wherein a rotating excitation magnetic field is combined with orthogonally measured magnetic signals. The operational principle of the proposed approach is systematically explained in the time and frequency domains, and an empirical model is developed to describe the quantitative relationship between stress magnitude, orientation, and orthogonal magnetic signals. Experimental validation is conducted to assess the feasibility of the proposed technique and confirm the accuracy of the theoretical principles and the empirical model. The experimental results indicate that RFSM is insensitive to the orientation of uniaxial stress. Specifically, the amplitude B_R linearly increases with stress magnitude, independent of stress orientation, while the phase $\phi$ decreases linearly with stress and is influenced by both stress magnitude and orientation. The RFSM signals can be effectively represented as the superposition of alternating current stress measurements or magnetic anisotropy stress signals measured orthogonally. The validation results demonstrate that the empirical model accurately predicts variations in B_x​ and B_y ​signals under different stress conditions. This study further highlights the necessity and advantages of orthogonal or multisensor configurations for evaluating complex stress states.