On the structural dynamics of laminated composite plates and sandwich structures; a new perspective on damping identification

Abstract

This paper presents the modelling and the dynamic characterization of laminated composite plates and sandwich structures in terms of stiffness and damping. The developments used in this paper are based on the analytical multilayer model of Guyader and Lesueur (JSV, 1978). The model considers linear shear, membrane and bending effects in each layer. The characteristics of the structure are determined by means of an equivalent thin plate methodology. The first main novelty of this paper consists in adapting this methodology for laminated plates (orthotropic multilayers with arbitrary orthotropic angle per layer). An experimental validation of this adaptation is presented for a laminated composite plate. Concerning the modelling of the structural loss factor, a space domain definition based on the spatial attenuation of a plane wave is compared to an energetic method and an equivalent definition based on the thin plate theory. The results show that the equivalent definition overestimates the loss factor in high frequencies since the thin plate theory only considers the flexural behaviour of the structure. On the contrary, the space domain definition (which give similar results as compared to the energetic one for lightly damped structures) considers the frequency dependent variation of the dynamic behaviour of the structure by means of the ratio between the group and phase velocities. The latter approach is considered to be more correct. The second main novelty of this article is on the experimental validation of this space domain definition. The structural loss factors of two sandwich structures are Article published in Journal of Sound and Vibration identified from measurements using modal, energetic and spatial methods. The results using the space domain definition are in very good agreement with the analytical predictions and the estimations of the modal and energetic methods for both plates for a large frequency band (up to 20 kHz), demonstrating the validity of the approach developed in this paper.

On the condensation of thick symmetric multilayer panels including dilatational motion

“…Guyader and Cacciolati [16] later adapted the previous model of Guyader and Lesueur to identify equivalent properties of isotropic multilayers. Note that this work has been recently extended to anisotropic multilayers [17]. Ege et al [18] compared the equivalent models of RKU and Guyader with the Lamb waves model and observed consistent results in terms of equivalent stiffnesses and slightly different damping loss factors.…”

Experimental methodology to assess the dynamic equivalent stiffness properties of elliptical orthotropic plates

“…Three different equivalent plate characteristics (anisotropic, orthotropic or elliptical orthotropic) have been assumed as well. Note that a similar equivalent methodology has already been studied with this analytical model for the anisotropic case on carbon fiber composite plates [21].…”

Numerical simulation analysis of a PGR exterior body structure considering vibroacoustic characteristics

“…The increasing demand for stable performance in harsh environments such as vibration and noise has led to the noise control problem of PGR exterior body to the forefront [18][19][20]. The results showed that the vibration of the EBS, sound field and damping coupling interface affected the noise in the PGR [21]. The vibration of the EBS produces noise, which in turn produces an additional response to the EBS because of the sound pressure [22][23][24].…”