The structural response of the thermoplastic composite joint subjected to out-of-plane loading

This paper presents a study on thermoplastic single-lap double rivet joints (SLDJ) with and without adhesive subjected to out-of-plane projectile impact and quasi-static concentrated loading. The three-dimensional finite element (FE) models considering strain-rate effects and damage evolution were developed and implemented in the commercial code Abaqus/Explicit through a user-defined subroutine VUMAT. The FE models were validated against the experimental results, in terms of the peak load, the maximum displacement and the dissipated energy. It was found that there were three stages in the load-displacement trace up to the failure, i.e. rivet slip, hole failure and laminate break for the rivet joint, and debonding, rivet slip and laminate break for the rivet joint with adhesive. The rivet joint with adhesive has a higher stiffness before debonding occurs; however, its out-of plane load carrying capacity is slightly lower than the rivet only counterpart. The validated models were used to study the failure mechanisms of SLDJ through the progressive failure simulation, and further to investigate the effects of boundary conditions, ply angle and impact energy on the impact response of the composite joints. The laminates with 45 degrees ply could be used to enhance the impact resistance of composite joint structures with the reduced damaged area.