Topology design of binary structures subjected to design-dependent thermal expansion and fluid pressure loads

The future perspective of using topology optimization to solve challenging design-dependent physics problems motivates the creation of methods with clear structural boundaries and well-defined volume. This paper develops the topology optimization of binary structures (TOBS) method to include design-dependent fluid pressure and constant thermal expansion loads. Topology design in thermoelastic and fluid pressure problems have been only handled separately up to date. To the authors' best knowledge, this is the first work to consider both type of loads simultaneously within a structural topology optimization framework. The TOBS method uses discrete design variables, sensitivity filtering, and formal mathematical programming (integer linear optimization) to achieve convergent and mesh-independent solutions. The discrete nature of the method presents attractive features when dealing with design-dependent body and surface loads. In this paper, we use the structural mean compliance and volume as functions for optimization. The sensitivity analysis is carried out using the adjoint and semi-analytical methods. Numerous examples are shown to design novel structural designs which perform well under the applied fluid pressure and thermal loads. The observed computational times signify the practicability of integer programming for structural optimization problems.