Analysis of a hybrid composite/metal bolted connection subjected to flexural loading

Abstract This paper presents the structural response of hybrid composite/metal bolted joints using an experimental investigation and finite element analysis. The primary motivation for this work is to provide alternatives to conventional hull construction techniques using modular hybrid construction methods. The main objective is to implement a watertight hybrid connection concept that provides access using removable panels on a ship hull. The hybrid joint developed is used to connect fiberglass reinforced composite panels to a metal sub-structure. An experimental study was conducted to quantify the performance of various hybrid joints with various geometries, loaded in flexure. The test results show that, for resisting bending loads, joints with metal cap plates can be made stronger and rotationally stiffer than standard bolted joints, while also mitigating opening of the joint, thereby improving the ability to seal the connection for watertight integrity. Local shell and detailed solid finite element analyses of the connections are presented. Simplified shell finite element models were developed for implementation into global models of the structure and good correlation with the test results was observed with respect to connection stiffness. Nonlinear response of the connection was predicted using detailed plane strain contact models to capture the three-dimensional effects. The results of this study were used to select a connection geometry, which was subsequently incorporated into the hydrostatic testing of a full-scale four-panel assembly.