FLOATING NODE METHOD AND VIRTUAL CRACK CLOSURE TECHNIQUE FOR MODELING MATRIX CRACKING DELAMINATION MIGRATION

摘要

Damage in composite materials generally occurs as a combination of different and interacting failure mechanisms, e.g. delamination and matrix cracking. Capturing these interactions accurately is essential to confidently model and predict progressive damage and failure. Many approaches have recently been proposed that explicitly model different failure mechanisms and attempt to capture their interaction [1-3]. However, no single strategy has yet surfaced as totally satisfactory. The present approach combines the Floating Node Method (FNM) [4] with the Virtual Crack Closure Technique (VCCT) [5,6] to explicitly account for different failure mechanisms and their interaction. Delamination, matrix cracking, and migration events are all modeled with the same FNM element using fracture mechanics-based failure and migration criteria. The approach is validated using recent experimental results in which a setup capable of isolating a single complete migration event was developed [7]. Migration is defined as the transition of a delamination from its current ply interface to a new interface via transverse ply cracking. The results obtained offer a simple, yet very challenging, benchmark for the validation of numerical and analytical approaches aimed at high-fidelity modeling of composite materials, such as the one proposed in the present paper.