Abstract Summary
Sandwich structures are encountered in numerous applications ranging from automotive and aerospace industry, to bridge construction. However, the design of these structures is a cumbersome task due to two reasons. Firstly, the performance of the sandwich configurations is both dependent on the acoustic and structural transmission path in the core, leading to a coupled vibro-acoustic problem. Secondly, the structures must comply with contradicting mass, noise and stiffness requirements. More specifically, the sandwich configurations need to be as light as possible to comply with strict environmental regulations, while they need to achieve good vibro-acoustic performance to obey restrictive noise regulations. On top of that, a restriction on the static stiffness performance of the structures is present in most applications. To facilitate this multi-functional and multi-physical design problem, optimization routines are important enablers. While extensive research is executed on the material and (structural) size optimization of both the panels and the core of the sandwich configuration, the systematic topological design of the vibro-acoustic core is yet to be explored. Therefore, in this work, a topology optimization framework is presented for the design of sandwich configuration cores to achieve extraordinary performance characteristics while considering the vibro-acoustic coupling in the core during the optimization. More specifically, the design domain of the optimization consists of a unit cell which is infinitely repeated in the in-plane direction. This design domain is optimized to maximize the corresponding sound transmission loss of the infinite periodic structure while the mass and structural stiffness are constrained with user-defined inputs. Novel cores are presented while the trade-off between the different conflicting requirements is investigated.
