This research will develop direct micromechanical simulation techniques to model damage accumulation in composite materials. Tools will be developed that are capable of evaluating the composite material deformation, fracture, damage accumulation and failure based on the underlying microstructural defects and the evolution of the microstructural state under multiaxial loading. These simulations will establish a direct relationship between the evolution of the microdamage accumulation and the loss of load-carrying capability of the bulk composite material.