Noise Reduction of Mechanoacoustic Systems by Topological Optimization Method

We consider the problem of reducing noise and vibration caused by harmonic sources. The main approaches that exist are the use of damping with different materials or the use of absorption nodes and the addition and redistribution of mass or stiffness. As an alternative and more effective approach, it is proposed to fill the volume of the structure with the optimal spatial configuration of the material. To research this direction, we consider the problem of topological optimization of mechanoacoustic systems characterized by the presence of a point harmonic vibration source. The main feature of the algorithm is the use of the active source power, which is determined by the imaginary part of the vibration velocity vector at the point of force application, as an objective function. The approach to finding the optimum is similar to the solid isotropic material with penalization (SIMP) algorithm. We have selected the parameters of the modified algorithm in order to ensure the efficiency of optimization. Numerical testing of the method was carried out on the problem of minimizing acoustic noise emitted by a square-shaped steel frame immersed in a fluid, when a periodic single force is applied to its wall. As a result of the algorithm, the distribution of the material inside the frame was obtained and a decrease in the average pressure in the outer boundary of the liquid was achieved in a wide frequency band.