Progressive failure analysis of marine sandwich joints with a modified material degradation model

The progressive failure analysis based on a modified stiffness degradation model was proposed to predict mechanical response of sandwich L-joints for ships. A representative volume element was established for the derivation of the modified material degradation model for two-dimensional orthogonal woven fabric structures based on micromechanical theory. The modified Shokrieh failure criterion and six field variables were applied in ABAQUS user subroutines. Three different coordinate systems were used to assign reasonable material orientation. The predictions of ultimate load, stress distribution, load-displacement curve and failure patterns were compared with experimental results. The good consistence indicates the effectiveness of the proposed stiffness degradation model. The FE results show the edge of the arc bracket is the stress concentration area due to the shear lag effect, and the declined slope of load-displacement curve is caused by delamination failure due to the stiffness difference of laminates and foam core.