NONLINEAR CORRECTING METHOD IN MEASURING METHOD FOR MAGNETOSTRICTIVE STRESS

摘要

PURPOSE:To determine the correct stress with good accuracy by a method wherein it is detected to which area the stress calculated from an output voltage of a magnetic anisotropy sensor belongs in comparison with a reference stress, and the correcting stress corresponding to the calculated stress is obtained on the basis of the gradient in the area. CONSTITUTION:The characteristic curve of the stress of a specimen is formed beforehand by dividing a value obtained by subtracting an offset value L0 from an output voltage of a magnetic anisotropy sensor corresponding to the change of the stress by the magnetostrictive sensitivity M. The characteristic curve is divided into a plurality of areas through linear approximation while a plurality of reference stresses St1, St2 are set. At the same time, the actual stress corresponding to each reference stress is obtained by a strain gauge. Thereafter, the stress of an object to be measured of the same magnetic material as the specimen which is obtained by converting the output voltage of the magnetic anisotropy sensor is compared with the stresses St1, St2, whereby to which area the stress belongs is detected. When the area of the calculated stress is detected, the correcting stress corresponding to the calculated stress obtained by converting the output voltage will be obtained on the basis of the gradient in the area.