METHOD FOR MEASURING INTERNAL STRESS OF SOLID BY PHOTOELASTICITY

摘要

PURPOSE:To measure internal stress with high sensitivity by providing polarizers before and behind a material to be inspected on an optical path of electromagnetic waves, turning the polarizers in the main axis direction while maintaining an angle of odd times pi/2 and receiving and integrating the change of the transmitted electromagnetic waves. CONSTITUTION:The light projected from a light source 4 which generates the continuous electromagnetic waves transmits the two polarizers 2 and the material 1 to be inspected and enters a photodetector 6. The detector 6 is synchronously controlled by a controller 7 in order to be synchronized with the turning of the polarizers 2. The polarizers 2 are turned by the controller 7 via a motor M while the angle of even times pi/2 is maintained in the mutual main axis direction. The photodetector 6 receives the information on the change of the transmitted electromagnetic waves by turning of the polarizers 2 and sends the same to a detector 9. The detector 9 measures the internal stress of the solid 1 by integrating and computing the signal. The internal stress of the solid material is thereby measured with the high sensitivity.