Data supporting the publication A shell-to-shell cohesive line element for efficient modeling of inter- facial cracking in overmolded stiffened panels

Manuscript submitted to the journal Computer Methods in Applied Mechanics and Engineering. Description: A novel structural cohesive element is proposed for the efficient modeling of debonding in composite panels with overmolded stiffeners. The formulation is based on three-node triangular Kirchhoff–Love shell elements for both the panels and the stiffeners, complemented by the Free Formulation (FF) membrane to enhance the in-plane bending response. The proposed cohesive element is conforming with orthogonal T-jointed shell elements. An appropriate definition of the displacement jumps, consistent with shell kinematics, enables a straightforward formulation while allowing the transmission of both cohesive forces and cohesive moments. The model is validated against mode I, mode II, and mixed-mode benchmark problems. The results show that the structural models based on the FF membrane delivered superior performance compared to those employing the Constant Strain Triangle (CST) formulation in most cases. A panel–stiffener debonding problem designed to promote stable crack propagation is also analyzed using both standard 3D cohesive elements and the proposed structural cohesive element with the FF membrane. The results demonstrate that the proposed models can employ coarser meshes than the standard cohesive element models, achieving more than a 95% reduction in CPU time, while maintaining comparable accuracy. Consequently, the proposed cohesive element, based on three-node, 18-DoF triangular shell elements, enables efficient analysis of stiffener debonding in laminated panels with complex overmolded stiffener grids. It is further envisioned that the model can be coupled with the cohesive element proposed in the reference [23] to simulate both ply delamination and panel–stiffener debonding in progressive failure analyses of composite structures.