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Multi-Scale Simulation of Delamination Migration

DAVID MOLLENHAUER, ERIC ZHOU, KEVIN HOOS, ENDEL IARVE, MICHAEL BRAGINSKY, TIMOTHY BREITZMAN and DANIEL RAPKIN

Abstract


A Discrete Damage Modeling (DDM) approach using a Regularized eXtended- Finite Element Method (Rx-FEM) formulation has been applied to a test specimen for characterizing delamination migration in laminated composites. The migration specimen is designed such that as a delamination propagates, the stress state alters such that delamination migration through a neighboring ply becomes favorable. The present research aims to use the DDM framework to simulate the local, micro-scale behavior at a delamination migration point. Additional functionality to the Rx-FEM formulation, required for this task, allows for Rx-FEM cracks of arbitrary shape. A four-point shear fracture specimen was used as empirical guidance in validating this capability. Excellent agreement between model and experiment was shown. A laminated effective-modulus representation of the test was then modeled using the DDM framework, establishing the point of delamination migration. Location of delamination migration was predicted accurately. A local, micro-scale model was constructed and applied at the location of migration. The micro-scale model consisted of arbitrary interacting cracks in resin-rich zones using the modified Rx-FEM formulation and standard cohesive zone disbonding between fibers and resin. Model predictions show great similarity to the initial shape of the migrating transverse cracks observed in experiment.

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