The goal of this project is to establish a computational framework for tailoring the structural stochasticity of microstructural materials to achieve desired properties. Based on this method, we propose a new structure design concept, “stochastically graded structures”, to enable effective manipulation of stress wave propagation by varying the local structural stochasticity while maintaining the material compositions and densities. The outcome of the proposed research will (i) lead to a quantitative understanding of the effect of structural stochasticity on the stress wave propagation behaviors, and (ii) accelerate the development of new structural materials for impact/blast protection.

Our group has also made strides in incorporating into topology optimization local failure criteria, such as stress and fatigue-life constraints. These constraints are common and critical design requirements for high-performance engineering applications, including vehicle structures. We have formulated techniques to efficiently impose maximum stress and minimum high-cycle fatigue-life constraints for large-scale problems. Our group formulated the first density-based topology optimization technique to incorporate fatigue-life constraints in the presence of non-proportional loading, which is common in many practical applications.