This study aims at developing a finite element model to predict the sound transmission loss (STL) of a multilayer panel
partially treated with a Magnetorheological (MR) fluid core layer. MR fluids are smart materials with promising
controllable rheological characteristics in which the application of an external magnetic field instantly changes their
rheological properties. Partial treatment of sandwich panels with MR fluid core layer provides an opportunity to change
stiffness and damping of the structure without significantly increasing the mass. The STL of a finite sandwich panel
partially treated with MR fluid is modeled using the finite element (FE) method. Circular sandwich panels with clamped
boundary condition and elastic face sheets in which the core layer is segmented circumferentially is considered. The MR
fluid core layer is considered as a viscoelastic material with complex shear modulus with the magnetic field and frequency
dependent storage and loss moduli. Neglecting the effect of the panel’s vibration on the pressure forcing function, the work
done by the acoustic pressure is expressed as a function of the blocked pressure in order to calculate the force vector in
the equation of the motion of the panel. The governing finite element equation of motion of the MR sandwich panel is
then developed to predict the transverse vibration of the panel which can then be utilized to obtain the radiated sound using
Green’s function. The developed model is used to conduct a systematic parametric study on the effect of different locations
of MR fluid treatment on the natural frequencies and the STL.
This study aims to investigate the effect of using magnetorheological elastomer (MRE)-based adaptive tuned vibration absorbers (ATVA) on the sound transmission in an elastic plate. Sound transmission loss (STL) of an elastic circular thin plate is analytically studied. The plate is excited by a plane acoustic wave as an incident sound and the displacement of the plate is calculated using corresponding mode shapes of the system for clamped boundary condition. Rayleigh integral approach is used to express the transmitted sound pressure in terms of the plate’s displacement modal amplitude. In order to increase sound transmission loss of the plate, the MRE-based ATVA is considered. The basic idea is to be able to change the stiffness of the ATVA by varying magnetic field in order to reduce the transmitted acoustic energy of the host structure in a wide frequency range. Here, a MRE-based ATVA under the shear mode consisting of an oscillator mass, magnetic conductor, coils and MRE is investigated. In order to predict the viscoelastic characteristics of the field-dependent MRE based on the applied magnetic field, the double pole model is used. Finally, MRE-based ATVAs are integrated with the plate to absorb the plate energy with the aim of decreasing the transmitted sound power. Results show that plate with integrated MRE-based ATVAs suppresses the axisymmetric vibration of the plate and thus considerably improves the STL. Parametric studies on the influence of the position of MRE-based ATVAs and the effects of applied current on their performance are also presented.