An Immersed Boundary Framework for Topology Optimization of Nonlinear Thermoelastic Structures with Internal Radiation

Thermoelastic structures pose a critical challenge to designers due to the inherent design dependence of thermal loading on structural thickness. This is further exacerbated by structural nonlinearity due to in-plane, and more importantly, the out-of-plane bending deformation that further increases the effective loading on the structure. During Phase I of this project, we have added significant new functionality to MAST that allowed us to perform topology optimization of nonlinear multiphysics problems with efficient adjoint-sensitivity analysis. The approach allows the definition of an optimization problem where different types of optimization variables and constraint functions can be simultaneously introduced. We have clearly established the importance of nonlinearity for thin-walled structures operating under thermal loading and have shown that while nonlinearity may not play a significant role for purely in-plane responses, they critically impact every aspect of responses involving out-of-plane deformation: displacement, stress distribution, and stability. The proposed Phase II effort will extend this foundation for topology optimization of three-dimensional structures with composite material modeling, multiple load cases, and internal cavity radiation. Efficiency of numerical approaches will be improved by using high-order adaptive analysis and efficient iterative solvers.