Stress concentration factors of reinforced square hollow section T-joints

Abstract

This paper reports on an investigation into the stress concentration factors of a reinforced Square Hollow Section T-joint under brace axial compression. The project consists of both experimental and numerical studies. A full-scale reinforced T-joint specimen was tested with the brace loaded under axial compression. The results were compared to those obtained from a finite element model and the model was observed to be able to predict the stress concentration factors satisfactorily. A parametric study was then conducted to understand the influence of the geometric parameters on the stress concentration factor at various hot-spots on the reinforced joint. The results of the parametric study show that the stress concentrations generally increase with increasing beta (brace to chord diameter ratio), and increasing 2gamma (chord diameter to thickness ratio). The results have shown that the plate reinforcement reduces the stress concentration factors at the joint as compared to the stresses of a similar unreinforced joint. It can be concluded that the doubler plate reinforcement may enhance the fatigue strength of the joint. Empirical equations to predict the stress concentration factors at various points of the doubler plate reinforced T-joint are proposed.