On the role of lengthscale in the prediction of failure of composite structures: assessment and needs

The role of modeling in the design of structural composite components against failure is discussed. Composite materials fail due to damage processes operating at several lengthscales. The interactions between these processes offer the principal challenges to applying mechanism-based models at structural scales beyond the ply level. A methodology is proposed to increase the efficiency of the design process, analogous to the 'building block' approach, which provides a framework for integrating mechanism-based models with the current experimentally-based design process. Available models are reviewed and their key elements identified. General concepts are illustrated via a discussion of the particular issues pertaining to notched components. Key steps needed to allow the evolution of the design process to the envisioned process are identified