Stiffening of restrained thermal structures via topology optimization

The majority of work in the thermal structures field has focused on reducing or eliminating thermal stresses by accommodating thermal expansion. In the modern day, several new applications, including engine exhaust-washed structures for embedded engine aircraft, are posing new design scenarios where this prescription is not possible. Thus it becomes necessary to utilize new design techniques to solve the problem of stiffening and stress reduction in thermal structures with restrained thermal expansion. In this work, a design scenario is presented to demonstrate the challenges associated with the design of thin shell structures in a thermal environment and the breakdown of common design methodologies. These challenges include a fundamental non-intuitiveness in the design space and the design dependency that occurs with thermal loading. Three different topology optimization formulations are investigated to solve this problem. The effectiveness of each of these methods is benchmarked against one another and general recommendations are made regarding effective design solutions for restrained thermal structures.