Topology optimization of bi-material in coupled systems of structure and infinite acoustic field was investigated. The finite element method and boundary element method were used to simulate the structure and acoustic fields, respectively. The stiffness matrix, the mass matrix, and the damping matrix were constructed based on the piecewise constant level set (PCLS) method. Minimization of the squared vibration amplitudes at specified points of the structure was chosen as the design objective, using the adjoint variable method to calculate the design sensitivities. Introducing the quadratic penalty method to satisfy the volume constraint, the optimization parameter was redefined to overcome its problem dependency by using the sensitivity information. Numerical results show that the vibration amplitudes can be reduced significantly, indicating the effectiveness of the optimization algorithm. The volume constraints are well satisfied under the same optimization parameters in different cases, showing the advantages of redefined optimization parameter. © 2022, Editorial Office of Journal of Vibration and Shock. All right reserved.
