Characterization of Modal Damping of Sandwich Plates

Abstract

The homogenization of the energy functional of a sandwich plate, its minimization and its discretization by finite element methods and modeling the viscoelastic core behavior by an hysteretic structural damping lead to the homogenized dynamic equation of a sandwich plate. The vibratory analysis permits the determination of the elastic eigenmodes and the characterization of the modal damping which will serve to the establishment of dynamical responses if we used the modal dynamic recombination method. The numerical results obtained show that the eigenmodes are not orthogonal to the damping matrix but are only weakly coupled. Besides, the modal damping matrix coefficients vary according to the ratio of the core thickness and the total thickness of sandwich plate and follow a second-order polynomial function of this ratio.

A methodology for damping measurement of engineering materials: application to a structure under bending and torsion loading

“…Most of the documented work on damping measurement focuses on composites (Brodt and Lakes, 1995;Wei and Kukureka, 2000;Hammami et al, 2005;Foss, 2007;Martı´nez-Aguirre and Elejaberrieta, 2010) and dampers which have a high damping ratio (Foss, 2007;Cai and Sun, 2010;Martı´nez-Aguirre and Elejaberrieta, 2010). There are less studies focusing on the damping of a real structure of several assembled parts (Chowdhury and Dasgupta, 2003;Orban, 2011).…”

Modal damping prediction of sandwich panel with visco-elastic thick core

“…where U i and U i are the dissipated energy for one cycle of the steady-strain vibration and the elastic energy for the ith mode [4], respectively…”

“…Assaf [3] developed a triangular finite element by considering a linear variation of the plane displacement through the thickness of each layer. This element was last used by Hammami et al [4] to characterize modal * Corresponding author: Unit of Mechanical Systems Dynamic, National School of Engineers of Sfax, Sfax BPW 3038, Tunisia. email: moezabd@yahoo.fr damping of the sandwich plate.…”

“…Assaf [3] developed a triangular finite element by considering a linear variation of the plane displacement through the thickness of each layer. This element was last used by Hammami et al [4] to characterize modal damping of the sandwich plate. Wang and Chen [5] employed a discrete layer annular finite element to determine the natural frequencies and modal loss factors of a three-layered annular plate with a viscoelastic core layer and two polar orthotropic laminated face layers.…”

Vibro-acoustical analysis and design of a multiple-layer constrained viscoelastic damping structure

“…Extend the FE model from a simple beam structure to an irregular shape structure [38,109,110] for the industrial usage. For a 3D geometry, the Biot damping model requires further manipulation to incorporate a more complicated form of Biot constants.…”