EFFECT OF CHORD LENGTH RATIO ON HOT SPOT STRESS DISTRIBUTION OF WELDED TUBULAR T-JOINTS UNDER AXIAL LOAD

摘要

Hot spot stress range is generally used in assessing the fatigue life of a tubular joint. For a tubular joint subjected to combined loads, it is necessary to know the stress distributions of the joint under different basic loads. It is generally believed that three geometrical parameters, namely chord thickness ratio, brace/chord diameter ratio and hrace/chord thickness ratio, have critical effect on the stress concentration and the stress distribution for a tubular T-joint subjected to basic loads. The effect of the chord length ratio on the stress concentration, however, is believed to be minor. In this study,the hot spot stress distributions along the weld toe for tubular T-joints with different values of chord length ratio under axial load are investigated using finite element method. Through the investigation of the finite element results of the analyzed T-joint models, it is found that the effect of the chord length ratio on the hot spot stress distribution of a tubular T-joint under axial load is remarkable when the chord thickness ratio is much smaller. Especially, the value and the location of the peak stress around the weld are influenced apparently. However, such effect is very little when the chord thickness ratio is bigger than certain value. As the effect of the chord length ratio on the hot spot stress distribution was generally neglected in previous study and design, such idea should be re-corrected when the chord thickness ratio is much smaller.