RESIDUAL STRESS EVALUATION APPARATUS AND RESIDUAL STRESS EVALUATION METHOD

摘要

PROBLEM TO BE SOLVED: To enable evaluation of internal residual stress of a resin molded product without breaking the same.SOLUTION: A resin molded product is irradiated with terahertz waves having a polarization direction as a first direction to acquire a first absorbance A1 of the resin molded product. The resin molded product is also irradiated with terahertz waves as a second direction different in a polarization direction by a predetermined angle from the first direction to acquire a second absorbance A2 of the resin molded product. Internal residual stress of the resin molded product is then evaluated using an absorbance difference &Dgr;A which is a difference between the first absorbance A1 and the second absorbance A2.