Response of clamped sandwich panels with viscoelastic core under random acoustic excitation
TL;DR: In this article, the acceleration response of square sandwich panels with clamped boundaries under a specific random acoustic excitation was evaluated by applying Galerkin's procedure and generalized harmonic analysis was used to compute the response spectrum.
Abstract: Both theoretical and experimental studies have been made to evaluate the acceleration response of square sandwich panels with clamped boundaries under a specific random acoustic excitation. Generalized harmonic analysis was used to compute the response spectrum. The modal frequencies and associated loss factors of the composite used in the analytical estimation of the response were obtained by applying Galerkin's procedure. The effects of modal cross coupling and of the core thickness on the response have been studied. The theoretical estimates of the response are compared with the results from the experiments for certain core thicknesses.
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TL;DR: In this article, free vibrations and the transverse response of sandwich plates with viscoelastic cores under wide-band random excitation are studied with special attention to the so-called pumping, thickness-shear and stretching modes.
Abstract: Free vibrations and the transverse response of sandwich plates with viscoelastic cores under wide-band random excitation is studied with special attention to the so-called pumping, thickness-shear and stretching modes. The quadratic displacement field is adopted for all displacement components of the core to accurately capture the higher modes excited by the wide-band excitation. The Love-Kirchhoff plate theory is used for the face layers. The viscoelastic behavior of the core is modeled by the Golla–Hughes–McTavish method. An analytical solution using the normal mode method is provided for the simply supported boundary conditions by including a different family of modes. The effects of some geometric and material properties on the frequencies, damping ratios and also root mean square responses are explored. The participation of the through-the-thickness deformation in the bending mode vibration of the top layer is also investigated, which is found to be mostly resulting from the second order term of the ...
22 citations
TL;DR: In this article, the authors explored an idea of adapting the static and dynamic material distribution of panels through embedded microvascular channels and strategically placed voids that permit the internal movement of fluids within the panels for structural dynamic control.
Abstract: The performance, integrity, and safety of built-up structural systems are critical to their effective employment in diverse engineering applications In conflict with these goals, harmonic or random excitations of structural panels may promote large amplitude oscillations that are particularly harmful when excitation energies are concentrated around natural frequencies This contributes to fatigue concerns, performance degradation, and failure While studies have considered active or passive damping treatments that adapt material characteristics and configurations for structural control, it remains to be understood how vibration properties of structural panels may be tailored via internal material transitions Motivated to fill this knowledge gap, this research explores an idea of adapting the static and dynamic material distribution of panels through embedded microvascular channels and strategically placed voids that permit the internal movement of fluids within the panels for structural dynamic control Finite element model and experimental investigations probe how redistributing material in the form of microscale voids influences the global vibration modes and natural frequencies of structural panels Through parameter studies, the relationships among void shape, number, size, and location are quantified towards their contribution to the changing structural dynamics For the panel composition and boundary conditions considered in this report, the findings reveal that transferring material between strategically placed voids may result in eigenfrequency changes as great as 100, 50, and 74% for the first, second, and third modes, respectively
3 citations
01 Jan 2016
TL;DR: In this paper, the influence of the one close natural frequencies of the asymmetric modes of a near modal response and the on modeling of the mid led to both geo layer, a single integral viscoelastic model is used.
Abstract: The nonlinear vibration of sandwich viscoelastic plates under wide investigated. The main focus is on the influence of the one close natural frequencies of the asymmetric modes of a near modal response and the on modeling of the mid led to both geo layer, a single integral viscoelastic model is used. The displacement field in the thickness direction is also assumed to be linear for the in Moreover, the Kirchhoff theory with the von solution is initiated by applying the perturbation method along with the Galerkin's method to obtain integro non with the aid of the Pseudo modal response and the minimum excitation intensity required for the nonlinear interaction between asymmetric modes
Additional excerpts
...(4) 0 = 1 2 ( 0 , ( ) + 0 , ( ) + 0 3, ( ) 0 3, ( ) ) 1 = 1 2 1 , ( ) + 1 , ( ) , 2 = 0 0 3 = 1 2 1 ( ) + 0 3, ( ) + 1 3 ( ) 0 3, ( ) + 0 , ( ) 1 ( ) =1,2 1 3 = 1 2 1 3, ( ) + 1 , ( ) 1 ( ) =1,2 , 2 3 = 1 2 2 3, ( ) , 0 33 = 1 3 ( ) + 1 2 1 ( ) =1,2 2 , 1 33 = 2 2 3 ( ) , 2 33 = 0...
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References
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Book•
01 Jan 1949
203 citations
TL;DR: In this article, a simple differential equation is derived to describe constrained-layer damping in nonsymmetric sandwich plates and beams composed of isotropic and homogeneous layers, and the natural boundary conditions related to this equation are determined.
Abstract: A simple differential equation is derived to describe constrained-layer damping in nonsymmetric sandwich plates and beams composed of isotropic and homogeneous layers. The natural boundary conditions related to this equation are determined and some typical numerical results obtained by this equation are given. The equation is valid within the linear theories of elasticity and viscoelasticity in the absence of any constraints on thicknesses, positions, symmetries, and densities of the layers.
202 citations
TL;DR: In this paper, the analysis of flexural vibration of unsymmetrical sandwich beams and plates, with viscoelastic cores, has been carried out and the influence of inclusion of inertia effects, other than transverse ones, on the response due to forced harmonic excitation has been reported.
Abstract: Analysis of flexural vibration of unsymmetrical sandwich beams and plates, with viscoelastic cores, has been carried out. In addition to transverse inertia effects, longitudinal translatory and rotary inertia effects have been included. Influence of inclusion of inertia effects, other than transverse ones, on the response due to forced harmonic excitation, is reported. Damping effectiveness, for each of the resulting families of modes of vibration, is evaluated for various non-dimensional parameters.
161 citations
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