Transient response analysis for sound proof structure with a curved panel supported by nonlinear springs

Abstract

In this paper, we report vibration analysis using fast finite element method for sound proof structure with body frames supported by nonlinear concentrated springs. The sound proof structure is consisted of a porous material sandwiched between a steel panel and a resin sheet. And the structures has curved surfaces. We use three-dimensional Finite Elements Method and Modal Strain and Kinetic Energy Method to express the dynamic motions of the structure. Restoring force of the nonlinear springs have cubic nonlinearity. The discretized equations for the global system in physical coordinate are transformed into the nonlinear ordinary coupled equations using normal coordinate corresponding to linear natural modes. This transformation yields computation efficiency. We computed transient response due to internal resonance in coupling modes between the nonlinear springs and the sound proof structure, under large impact force. We found out influences of damping on nonlinear transient responses.