Modelling delamination migration using virtual embedded cohesive elements formed through floating nodes

Delamination migration is a common failure mode for composite laminates and the modelling technique remains challenging. For a complete progressive failure modelling, failure modes including delamination, matrix cracking, and the interaction between them should necessarily be considered. Existing methods may be effective for delamination or matrix cracking, but the situation becomes difficult when all of these failure modes are considered together in a unified framework. In this study, a new numerical framework based on floating node method is proposed to study delamination migration problem. A few discrete cohesive cracks are inserted into one element to offer multiple optional crack paths. Crack propagation due to delamination and matrix cracking can be modelled without remeshing. Element partition is treated in a convenient way which has simplified the implementation. And severe distortion of sub-element which may arise in a traditional element partition algorithm can be avoided. The proposed method is implemented through the ABAQUS user subroutine UEL and validated by comparing with experiments. The proposed numerical method has provided a framework for the modelling of delamination migration and also explored a method to model multiple discrete cracks within one element.