Topology optimization of single and double panels for improved sound insulation in specific frequency bands.

In this work, we investigate the potential of considering a non-uniform material distribution in the design of panel partitions, in order to achieve a superior vibroacoustic performance close to a given target frequency. In order to achieve this goal, we apply numerical topology optimization to find the optimal material thickness distribution for both single and double panels. Two formulations of the optimization problem are employed: in the first one, we suppress the resonance dips in the sound transmission loss by simply pushing the system eigenfrequencies far away from the target frequency. In the second formulation, we directly maximize the sound transmission loss of the system at the target frequency. In the iterative design process, the panels are modelled by mechanical plate finite elements. For double panels, the vibro-acoustic coupling between the panels and the internal air cavity, which is modelled analytically, is accounted for. The sound insulation properties are evaluated by transmission loss computations through hybrid Deterministic-Statistical Energy Analysis (Det-SEA) simulations. The method is applied considering different target frequencies in the audible range and focusing on practically relevant design cases. For both single PMMA panels and double glazing panels, it is demonstrated how a non-uniform thickness distribution allows for significant transmission loss improvements close to the target frequency, that are in the range of 5-15 dB with respect to uniform panels with the same mass. [ABSTRACT FROM AUTHOR]