265 / 2021-04-15 18:58:55

Simultaneous optimization of damping layer and thickness profile of an Acoustic Black Hole Plate for suppressing sound radiation

Acoustic black hole,sound radiation,simultaneous optimization,damping layer,thickness profile

Vibro-acoustics and Structure-borne Noise

In a plate embedded with acoustic black hole (ABH), both the thickness profile and the damping layer are essential components to achieve the ABH effect. The diminishing induces wave energy focalization in local areas of the plate, so that effective energy dissipation can be obtained employing a small amount of damping layer. ABH effect shows a great potential for vibration and noise suppression, which has been extensively investigated in the recent decade. Aiming at achieving efficient sound radiation reduction, this paper reports a general methodology for simultaneously optimizing the thickness profile of ABH indentation and the damping layer’s layout coated on the surface of an ABH plate. Those two sets of strong coupled design variables are alternatively nested and optimized in the main procedure. Modelling of ABH plates is implemented and the dynamic properties are solved using Abaqus and Python. A plate embedded with two ABH indentations is conducted as numerical example. Comparing to the ABH plate with non-optimized thickness profile and with damping layers intuitively coated at the central area of the ABH indentation, sound radiation reduction can be obtained in given frequency ranges adopting the proposed optimization method. Moreover, results demonstrate the necessity of adjusting the damping layer’s layout because of the energy concentration characteristic induced by ABH indentations in the plate, especially for suppressing sound radiation in low frequency range below the characteristic frequency of ABH.