Progressive Damage and Failure Predictions of T-Pull and Side Bend Tests of Composite Joints

This paper presents blind progressive damage and failure predictions conducted for typical aerospace composite structural components under various loading conditions. This blind prediction exercise was organized by the United States Air Force Research Lab (AFRL) under the Technical Cooperation Program (TTCP). The studied structural component is a stiffened laminated composite panel. The predicted load cases include T-pull, side bend, and mixed shear, with three defect levels, including pristine, tip defect, and throat defect. The blind predictions in this paper were performed with a continuum damage model, Enhanced Schapery Theory (EST), which was developed for versatile progressive damage and failure analyses (PDFA) for laminated composites. Highly accurate blind prediction results were obtained for the T-pull and mixed shear cases. For the side bend cases, the first-round blind predictions were inaccurate, due to the model not including the possibility for noodle-web debonding. With the noodle-web correctly modeled using interface elements, the second-round predictions became significantly more accurate. Overall, this blind prediction exercise validates and confirms the accuracy of the EST model developed for versatile PDFA of composites.