Concurrent multi-level model for damage evolution in microstructurally debonding composites

This paper develops an adaptive concurrent multi-level computational model for multi-scale analysis of composite structures undergoing damage initiation and growth due to microstructural damage induced by debonding at the fiber–matrix interface. The model combines macroscopic computations using a continuum damage model developed in a preceding paper [Raghavan, P., Ghosh, S., 2005. A continuum damage mechanics model for unidirectional composites undergoing interfacial debonding. Mech. Mater. 37 (9), 955–979.] with explicit micromechanical computations of stresses and strain, including explicit debonding at the fiber–matrix interface. The macroscopic computations are done by conventional FEM models while the Voronoi cell FEM is used for micromechanical analysis. Three hierarchical levels of different resolution adaptively evolve in this to improve the accuracy of solutions by reducing modeling and discretization errors. Three levels include: (a) level-0 of pure macroscopic analysis using a continuum damage mechanics (CDM) model; (b) level-1 of asymptotic homogenization based macroscopic–microscopic RVE modeling to monitor the breakdown of continuum laws and signal the need for microscopic analyses; and (c) level-2 regions of pure micromechanical modeling with explicit depiction of the local microstructure. Two numerical examples are solved to demonstrate the effectiveness and accuracy of the multi-scale model. A double lap bonded composite joint is modeled for demonstrating the model’s capability in handling large structural problems.