Nonlinear vibro-acoustic behaviors of coupled sandwich cylindrical shell and spring-mass-damper systems

This paper is concerned with the structural-acoustic analysis of a coupled sandwich cylindrical shell and nonlinear spring-mass-damper system immersed in an infinite acoustic medium. The restoring force of each spring in the spring-mass-damper system is assumed as a general polynomial function of the spring deformation, from which the nonlinear quadratic, cubic and quartic springs can be directly recovered. A modified variational approach is employed to formulate the nonlinear dynamics model of the coupled structural system, and the exterior acoustic fluid is computed by a time-domain Kirchhoff boundary integral formulation. The structural and acoustic models are coupled together through the compatibility conditions on their interface. The proposed model is validated by comparing the solutions obtained from the finite element/boundary element method and those available in the literature. Very good agreement between the predicted results and the reference solutions is achieved. Individual contributions of circumferential wave modes of the sandwich cylindrical shell to the vibration and acoustic responses of the coupled nonlinear structural system are examined. The effects of the amplitude and excitation frequency of the external loads, and different types of nonlinear springs (including the quadratic, cubic and quartic nonlinear springs) on the vibration and sound radiation behaviors of the structural system are investigated. (C) 2019 Elsevier Ltd. All rights reserved.