Evaluation of Stress Concentration Factor at Weld Toes in Welded Joints by Means of the Thermoelastic Stress Analysis

Abstract

The stress concentration factor at a weld toe in a welded joint is a very important factor of fatigue strength in welded structures. Since the shapes of weld toes are individually different, it is not appropriate to evaluate stress concentration factors at weld toes using numerical analysis such as FEM. In order to evaluate practically and accurately stress concentration factors at weld toes, thermoelastic stress analysis method (TSA), which is a stress analysis technique based on the measurement of infrared emission from the surface of a body subjected to cyclic loading, was applied to the measurement of stress distributions near weld toes. In this study, stress concentration factors evaluated by TSA were extremely lower than comparable numerical results due to the resolution limit of the infrared camera used. When stress distributions near weld toes measured by TSA were corrected by the empirical equation using toe radius, stress concentration factors evaluated by TSA agreed with numerical values within 25%.