Fracture modeling of curved composite shell structures using augmented finite element method

•A nonlinear AFEM based on dynamic implicit algorithm is proposed to improve the numerical convergence.•The cohesive element with shell kinematics is incorporated to describe the distinct fracture behaviors in composites.•A coordinate transformation system is proposed to describe the spatial crack trajectory in curved shell structures.•The complex fracture behaviors in some composite curved shell structures have been thoroughly investigated. This paper presents an augmented finite element method for the fracture modeling of curved composite shell structures considering geometric nonlinear effects. We first derive the composite shell AFEM (CS-AFEM) formulation using a dynamic implicit algorithm, which enhances the numerical convergence when dealing with unstable crack propagations. Besides, the cohesive zone model featuring with shell kinematics is incorporated into the CS-AFEM to describe the quasi-brittle fracture behaviors of composite laminates. Furthermore, a coordinate transformation scheme is proposed to describe both the local material orientation and the crack evolving path in the curved shell structures. Finally, several benchmark examples are numerically investigated, and the capability of the proposed method in modeling the arbitrary evolving cracks in curved composite shell structures has been thoroughly demonstrated.