Topological design of sandwich structures filling with poroelastic materials for sound insulation

Abstract The poroelastic material is often used as a sandwich core due to its lightweight and excellent sound insulation and absorption, and the research revealed that poroelastic materials with macro- or meso-holes could further improve its sound insulation performance. This study proposes a topology optimization approach to design poroelastic cores of sandwich structures for sound insulation. The mixed displacement/pressure (u/p) formulation based on Biot's theory and the ersatz material model are used to overcome the potential difficulties in topology optimization. The floating projection topology optimization method (FPTO) for maximizing sound transmission loss (TL) of sandwich structures filling with poroelastic materials is established based on the floating projection constraint, which simulates 0/1 constraints of the design variables. Some 2D and 3D numerical examples are given to demonstrate the capability and effectiveness of the proposed topology optimization algorithm. The results show that the distribution of the poroelastic material often concentrates at some locations. The traditional sandwich structures often have periodic cores, considering the ease of manufacture and the resistance of uncertain external loads. Therefore, topology optimization of periodic structures for sound insulation is also investigated in this paper. The numerical examples indicate that optimized periodic cores of sandwiches make the poroelastic material to be distributed evenly within the design domain but slightly scarify the sound insulation performance.