Topology optimization of PCLD on plates for minimizing sound radiation at low frequency resonance

Topology optimization of passive constrained layer damping (PCLD) treatment patched on thin plates with respect to sound radiation at low frequency resonance is investigated. An extended solid isotropic material with penalization (SIMP) model is described using an interface finite element model for viscoelastic layer. Then the given FE mesh for base structure can remain the same during the optimization process. The objective function, radiated sound power, is simplified by using sound radiation mode and modal strain energy method, the merit of which is the complex dynamic equations of the composite plate need not to be solved and only modal analyses for the associated undamped modal equations are required. Numerical and experimental results show that significant reductions of the sound power are achieved. Two optimal topologies of the PCLD patches are analyzed. It's shown that to minimize the sound radiation power at low frequency, not only the structural damping but also the volume velocity should be concerned.