SCANNING STRESS MEASUREMENT METHOD BY LASER PHOTOELASTICITY - (1ST REPORT - STRESS MEASUREMENT BY SYNTHESIZED METHOD)

Optical birefringence is measured by a high-frequency modulation metho d using a photoelastic modulator and polarized laser. A modified synth esized method was developed and applied for the measurement of stress distributions of a glass plate. The distributions of the differences o f principal stresses and their directions were obtained directly by th is method. The stress distributions under tensile load of a pulled rec tangular glass plate with a hole at its center were measured. The resu lts of stress distributions agreed with the analytical results. It was confirmed experimentally that the spatial resolution of stress measur ement was the same as the diameter of the laser light. The stress at m any points could be obtained quickly by the synthesized method and sca nning stress distribution measurement was realized.