Modeling the mechanical behavior of torque-tightened screw lap joints

Abstract

This paper presents an analytical approach to model the mechanical behavior of pre-tightened / torque-tightened screw lap joints under axial loading through a spring-based method. The presence of pre-torque in a screw joint significantly influences the load-deformation behavior since it induces frictional forces between the joint components. These frictional forces introduce different modes of deformation in the joint and are captured here by modeling the entire joint as a spring-mass system where the individual joint components and their deformation modes are approximated by linear springs. Subsequently, the whole model is presented by a set of equilibrium equations, which are solved to acquire the mechanical behavior of the screw lap joint. The proposed analytical model is validated against the performed experimental results and predictions from the 3D finite element model. Finally, the effect of different pre-loads and clearances on the behavior of the screw lap joints is analyzed through the proposed model.