Eigenvalue Analysis and Impact Response Analysis for T-shaped Structures with New Acoustic Black Hole Including Residual Thickness Supported by Nonlinear Concentrated Springs

Abstract

This paper describes analysis using finite element method with Model Strain Energy Method for steel structures having a T-shaped cross section supported by nonlinear concentrated springs under impact load. An edge of the rib plate in the T-shaped structure has an Acoustic Black Hole with residual thickness. A viscoelastic damping layer is covered on the acoustic black hole. Finite element for the nonlinear springs with hysteresis are expressed and are connected to the T-shaped structures modeled by linear solid finite elements in consideration of complex modulus of elasticity. We calculated modal loss factors and transient responses using the eigen modes including coupled motions between the non-linear springs and the T-shaped structures. From the dominant eigen modes and the time histories, we clarified effects of an Acoustic Black Hole with residual thickness and nonlinear springs on the nonlinear damped responses.