Linearization Method of Output vs. Stress in Stress Measurement Using Magnetic Anisotropy Sensor

Abstract

In the stress measuring method utilizing the magnetoelastic effect, the relatinonship between the sensor output and the applied stress is non-linear and the output becomes saturated under a large applied stress. In measuring an object with unknown residual stresses, the applied stress cannot be measured precisely because of the nonlinear relationship. Two outputs after ac demagnetization in two directions, parallel and perpendicular to the applied stress, are measured and the ratio of their sum/defference is calculated. The relationship is found to be almost linear in wide stress range and the influence of sensor lift-off is eliminated.