Delamination analysis of multi-angle composite curved beams using an out-of-autoclave material

Corners of composite curved beams can easily experience delamination under opening or closing bending moments. Existing literature on the delamination of curved laminated beams, however, is limited to unidirectional and cross-ply laminates with 0° and 90° layers and two-dimensional (2D) plane strain finite element analysis. This study experimentally and analytically investigates the failure behaviors of curved composite structures under four-point bending. Multiangle laminates manufactured using an out-of-autoclave prepreg were examined. A three-dimensional (3D) finite element model was created and analyzed with cohesive elements at the interfaces of adjacent plies. In the experiments, delamination dominated the failure of the curved laminates with several opening cracks. Multiple delamination positions were predicted in the analyses. Double cantilever beam specimens were tested and analyzed for a reference point for selecting cohesive parameters. Several cohesive parameters were selected and discussed. Predicted failure loads matched the experimental results well with 5.8% error when the model simulated a sufficient number of factors of the real test.