High fidelity analysis to predict failure in T-joints

Composite T-joints and similar skin-stiffener joints have a central role in aerospace structures. However, their accurate numerical analysis is still a great challenge due to their complex geometry and stress state during loading. In this work, an experimentally validated high-fidelity finite element model is developed to simulate the failure of a T-joint subjected to tensile loading. For the first time in literature, the model accounts for the shape of the manufactured filler, ply thickness variability in the laminate, stress gradient across the ply thickness, thermal stresses and in-situ mechanical properties. A new phenomenon called "filler effective ply thickness" is introduced to address the increased strength of the filler when embodied in a laminate. With this method, the model predicted the location and the failure initiation load within 5% accuracy of the experimental specimens, whereas conventional approaches using unidirectional strength significantly underpredicted the strength of the joint.