Failure analysis of a hybrid composite structural beam

The purpose of this study was to identify the failure mode of a particular composite structural beam developed for the civil infrastructure market and to develop a strength prediction that could be utilized in fatigue life predictions. First, a global–local finite element stress analysis is utilized to examine the possibility of compression failure. We then investigate the possibility of a delamination failure using a successive sub-modeling approach that allows detailed analysis of the inter-laminar stresses in regions of high stress gradients, including free edges and tapered laminates. The results of the analyses are compared with experimental test data from full-scale bending tests. The results indicate a compression dominated failure in the top flange in the vicinity of the load patch. This study highlights the difficulty in applying a stress-based approach to predicting delamination failure, particularly in complex laminated structures.