We present a new multiscale model for failure analysis of thin composite structures. The present model is based on the asymptotic homogenization method with multiple spatial scales. The proposed approach is a generalization of the elastostatic Caillerie-Kohn-Vogelius theory to study the failure mechanics of thin composite plates under static and dynamic loads. We employ a model reduction methodology based on the eigendeformation concept to minimize the computational burden. An efficient n-partition computational homogenization model is developed for simulation of large scale structural systems without significantly compromising on the solution accuracy. The proposed model is verified against direct 3-D finite element simulations.