Semi-Active Sound Transmission Control of Sandwich Panels Treated with MR Fluid Core Layer

2018 ◽  
Author(s):  
Masoud Hemmatian ◽  
Ramin Sedaghati
Keyword(s):  
Sandwich Panels ◽  
Sound Transmission ◽  
Core Layer ◽  
Transmission Control ◽  
Mr Fluid ◽  
Fluid Core

Sound Transmission Loss of Adaptive Sandwich Panels Treated With MR Fluid Core Layer

2016 ◽  
Author(s):  
Masoud Hemmatian ◽  
Ramin Sedaghati
Keyword(s):  
Magnetic Field ◽  
Applied Magnetic Field ◽  
Transmission Loss ◽  
Sandwich Panels ◽  
Sound Transmission ◽  
Core Layer ◽  
Sound Transmission Loss ◽  
Mr Fluid ◽  
Low Frequencies ◽  
Fluid Core

This study aims to investigate the sound transmission loss (STL) capability of sandwich panels treated with Magnetorheological (MR) fluids at low frequencies. An experimental setup has been designed to investigate the effect of the intensity of the applied magnetic field on the natural frequencies and STL of a clamped circular plate. A multilayered uniform circular panel comprising two elastic face sheets and MR fluid core layer is fabricated. It is shown that as the applied magnetic field increases, the fundamental natural frequency of the MR sandwich panel increases. Moreover, the STL of the panel at the resonance frequency considerably increases under applied magnetic field. Furthermore, an analytical model for the STL of the finite multilayered panels with MR core layer is developed and compared with the experimental measurements. The MR core layer is treated as a viscoelastic material with complex shear modulus. It is shown that good agreement exists between the analytical and experimental results. Parametric study has also been conducted to investigate the effect of face sheets and core layers’ thickness.

Nonlinear vibration analysis of circular/annular/sector sandwich panels incorporating magnetorheological fluid operating in the post-yield region

2020 ◽  
pp. 1045389X2097547
Author(s):  
Reza Aboutalebi ◽  
Mehdi Eshaghi ◽  
Afshin Taghvaeipour
Keyword(s):  
Magnetic Field ◽  
Nonlinear Vibration ◽  
Dynamic Characteristics ◽  
Sandwich Structures ◽  
Sandwich Panels ◽  
Core Layer ◽  
Experimental Results ◽  
Mr Fluid ◽  
Maximum Deformation ◽  
Annular Sector

This study offers a comprehensive analysis on the nonlinear vibratory behavior of circular, annular, and sector sandwich panels containing magnetorheological (MR) fluid as the core layer. Due to the large deformation experienced by the sandwich structures, the MR fluid operates in the post-yield region, in which the shear strain and shear stress are nonlinearly dependent. The post-yield characteristics of the MR fluid are quantified using the experimental results available in the literature. The present study also employs the experimental results presented in the literature on the dynamic characteristics of a MR based sandwich circular plate to demonstrate accuracy of the results. To identify governing equations of motion of the structures, a finite element approach based on von Karman formulations is employed. Moreover, displacement control strategy is used to solve the extracted nonlinear equations and evaluate dynamic characteristics of the MR based circular/annular/sector sandwich plates in terms of resonant frequencies and loss factors. This study highlights the effect of post-yield behavior of the MR fluid in the nonlinear vibration attenuation of MR sandwich structures, under different levels of magnetic field. Also, the effects of maximum deformation and magnetic field on the functionality of the MR fluid are comprehensively investigated.

VIBRATION AND DAMPING STUDIES ON A HOLLOW SANDWICH BOX COLUMN WITH A VISCOELASTIC/ELECTRORHEOLOGICAL/MAGNETORHEOLOGICAL FLUID CORE LAYER BY THE FINITE ELEMENT METHOD

2008 ◽  
Vol 08 (04) ◽  
pp. 531-546 ◽  
Author(s):  
K. RAM KUMAR ◽  
N. GANESAN
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Natural Frequencies ◽  
Core Layer ◽  
Viscoelastic Layer ◽  
Complex Eigenvalue ◽  
The Finite Element Method ◽  
Mr Fluid ◽  
Fluid Core ◽  
Element Method

In this paper, the vibration and damping of a hollow sandwich box column containing a viscoelastic layer (VEL) or an electrorheological (ER) or magnetorheological (MR) fluid core with a constraining layer are analyzed and a comparison of performance is made. The hollow sandwich box column comprises two skin plates and a VEL/ER/MR fluid core layer. The finite element method is used to study the vibration and damping behaviors of the column. The natural frequencies and modal loss factors are obtained by solving the complex eigenvalue problem. The modal dampings and natural frequencies of the column are calculated for various electric as well as magnetic fields and their performance is compared with that of the viscoelastic core layer for the clamped-free boundary condition. Effects of core thickness, electric voltage and magnetic field on the vibration behavior of the sandwich box column are investigated.

Active damping of sound transmission through an electrorheological fluid-actuated sandwich cylindrical shell

2018 ◽  
Vol 22 (3) ◽  
pp. 833-865 ◽  
Author(s):  
Seyyed M Hasheminejad ◽  
Masoud Cheraghi ◽  
Ali Jamalpoor
Keyword(s):  
Cylindrical Shell ◽  
Sliding Mode Control ◽  
Transmission Loss ◽  
Sliding Mode ◽  
Sound Transmission ◽  
Core Layer ◽  
Electrorheological Fluid ◽  
Sound Transmission Loss ◽  
Mode Control ◽  
Fluid Core

An exact model is proposed for sound transmission through a sandwich cylindrical shell of infinite extent that includes a tunable electrorheological fluid core, and is obliquely insonified by a plane progressive acoustic wave. The basic formulation utilizes Hamilton’s variational principle, the classical and first order shear deformation shell theories, the Kelvin–Voigt viscoelastic damping model (for the electrorheological fluid-core layer), and the wave equations for internal/external acoustic domains coupled by the proper fluid/structure compatibility relations. The Fourier–Bessel series expansions are used to arrange the governing (coupled) system equations in state-space form. The classical Sliding Mode Control law is then applied to semi-actively reduce sound transmission through the composite cylinder by smart variation of stiffness and damping characteristics of the electrorheological fluid-core actuator layer according to the control command. Numerical results present both the uncontrolled and controlled sound transmission loss spectra of the sandwich cylindrical shell at three angles of incidence for three distinct sets of material input parameters that represent the electric-field dependency of the complex shear modulus of the electrorheological fluid-core layer. The superior soundproof performance of electrorheological fluid-based sliding mode control system in avoiding the highly detrimental sound transmission loss dips occurring throughout the critical resonance and coincidence regions is demonstrated. Likewise, remarkable enhancements in the sound insulation characteristics of the electrorheological fluid-actuated structure utilizing the first or second electrorheological fluid material model are achieved within the stiffness-controlled region, especially at lower frequencies in near-grazing incidence situation. A number of limiting cases are introduced and validity of the formulation is confirmed by comparison with the available data.

Prediction of Sound Transmission Loss for Finite Sandwich Panels Based on a Test Procedure on Beam Elements

2013 ◽  
Vol 135 (6) ◽  
Author(s):  
Zhongchang Qian ◽  
Daoqing Chang ◽  
Bilong Liu ◽  
Ke Liu
Keyword(s):  
Sandwich Panel ◽  
Transmission Loss ◽  
Test Procedure ◽  
Sandwich Panels ◽  
Sound Transmission ◽  
Expansion Method ◽  
Bending Stiffness ◽  
Sound Transmission Loss ◽  
Modal Expansion ◽  
Beam Elements

An approach on the prediction of sound transmission loss for a finite sandwich panel with honeycomb core is described in the paper. The sandwich panel is treated as orthotropic and the apparent bending stiffness in two principal directions is estimated by means of simple tests on beam elements cut from the sandwich panel. Utilizing orthotropic panel theory, together with the obtained bending stiffness in two directions, the sound transmission loss of simply-supported sandwich panel is predicted by the modal expansion method. Simulation results indicated that dimension, orthotropy, and loss factor may play important roles on sound transmission loss of sandwich panel. The predicted transmission loss is compared with measured data and the agreement is reasonable. This approach may provide an efficient tool to predict the sound transmission loss of finite sandwich panels.

Dynamic Response of Sandwich Anisotropic Flat Panels to Explosive Pressure Pulses

2001 ◽  
Author(s):  
Terry Hause ◽  
Liviu Librescu
Keyword(s):  
Dynamic Response ◽  
Detailed Analysis ◽  
Fiber Orientation ◽  
Sandwich Structures ◽  
Sandwich Panels ◽  
Core Layer ◽  
Time Dependent ◽  
Pressure Pulses ◽  
The Face ◽  
Advanced Model

Abstract This paper addresses the problem of the dynamic response in bending of flat sandwich panels exposed to time-dependent external pulses. The study is carried out in the context of an advanced model of sandwich structures that is characterized by anisotropic laminated face sheets and an orthotropic core layer. A detailed analysis of the influence of a large number of parameters associated with the particular type of pressure pulses, panel geometry, fiber orientation in the face sheets and, presence of tensile uni/biaxial edge loads is accomplished, and pertinent conclusions are outlined.

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