Parametric equations to predict LJF of completely overlapped tubular joints under lap brace axial loading

• New parametric equations are proposed to predict LJF of the joint.
• Significative recommendations are proposed to reduce the LJF of the joint.
• The T/Y-joint equations are not fit for predicting LJF of the joint.

This paper presents parametric equations to predict the local joint flexibility (LJF) of completely overlapped tubular joints under lap brace axial loading. Finite element (FE) package MARC is adopted to simulate the joint with 8-node thick shell and 20-node solid elements, respectively. The FE method is calibrated and verified based on the existing experimental results of completely overlapped tubular joint specimens. A comprehensive parametric study is subsequently conducted to investigate the effect of non-dimensional parameters on the LJF. Significative recommendations are presented to reduce the LJF of the joint. A set of parametric equations are developed based on 5184 8-node thick shell FE models and have been assessed against the acceptance criteria of Fatigue Guidance Review Panel. The comparison of LJF between the proposed parametric equations and the existing T/Y-joint parametric equations shows that the use of the latter to predict LJF of completely overlapped tubular joints may not necessarily be appropriate.