A Discontinuous/continuous Galerkin method for modeling of interphase damage in fibrous composite systems

A Discontinuous Galerkin (DG) interface treatment embedded in a Continuous Galerkin formulation is presented for simulating the progressive debonding of bi-material interfaces. The method seamlessly tracks the progression from perfect adhesion to interface softening and finally to complete separation without resorting to node-to-node springs or deletion of connectivities. While the formulation is inspired by an augmented Lagrangian approach, it does not introduce multiplier fields to enforce the continuity conditions, resulting in a pure displacement method amenable to traditional symmetric positive-definite solvers. The study of fibrous composites serves as the application in the present work. The constitutive behavior of the interface is modeled within an energetic framework from which the initiation criterion and softening response emanate. Numerical simulations are conducted for various loading cases on a fiber-matrix unit cell that highlight the performance of the method on crude meshes.