Acoustic topology optimization of the material distribution on a simply supported plate
* Presenting author
Lightweight plates typically have a low transmission loss due to their low mass. Since coincidence typically plays a role at high frequency, the TL can be increased with roughly 6 dB by doubling the thickness of the plate. By distributing the additional material in a non-uniform manner, a higher increase in TL can be achieved in a limited frequency band due to modal behavior. A good material distribution strategy is needed to reduce the transmitted sound in a certain frequency range. Here, the optimal material distribution at a single frequency and in a frequency band is investigated for a small simply-supported plate. The TL is modelled within the hybrid Finite-Elements-Statistical-Energy-Analysis framework to achieve a low computational cost while maintaining a high prediction accuracy. Using mass distribution, the TL is increased by shifting eigenfrequencies of the plate and creating stop bands. This is achieved by locally adding mass that disturbs the mode shapes by altering the bending stiffness of the plate. For a 1x1m2 PMMA-plate, an increase up to 33 dB in the TL is achieved for the single frequency case and between 3 and 30 dB for a 50 Hz frequency band.