Experimental Stress Separation Technique Using Thermoelasticity and Photoelasticity and Its Application to Fracture Mechanics

摘要

This paper describes an experimental study on full-field stress separation from thermo-elasticity and photoelasticity measurements and its application to estimation of stress intensity factor and the J-integral. Thermoelastic stress analysis (TSA) and photoelastic stress analysis (PSA) have been developed as full-field visualization methods of stress distribution. Only the sum of the principal stresses can be measured by TSA, while only the difference of the principal stresses can be measured by PSA. In this study, the hybrid stress separation measurement technique developed by the present authors using both of these methods was applied for determining distribution of all individual stress components in a center-cracked plate subjected to mechanical load. Stress intensity factor and the J-integral were calculated from the obtained stress distribution. In addition to the conventional calculation method, near-tip exclusive domain integral method was proposed, in which the J-integral was evaluated without using degraded experimental stress distribution data near the crack tip. It was found that these fracture mechanics parameters can be evaluated with good accuracies by the present technique.