PREDICTION OF STRESS CONCENTRATION FACTORS IN UNLAPPED SQUARE HOLLOW "K" JOINTS BY THE FINITE ELEMENT METHOD

Abstract

The paper sets out to discover numerically the effect of brace spacing on stress concentrations in welded square hollow section 'K' joints. Thin shell theory and isoparametric formulation are employed to obtain equilibrium equations, which were solved by the frontal solution code developed for this purpose. Thereafter, the effect of brace spacing was investigated by varying the spacing between the two braces and making computer runs. The results obtained for the present study show a gradual deterioration in strength as the spacing between the two braces was increased. However, due to geometrical differences between the square hollow section and the tubular 'K' joints, it was considered not necessary to compare results of present work directly with published ones on tubular 'K' joints in the literature. It was, however, observed that the trend in behaviour between the tubular and the square section 'K' joints is similar. Thus, the present investigation and others in the literature show that lapped tubular and hollow section 'K' joints are stronger than unlapped joints for the same cross-sections.