Elasto-acoustic response damping performance of a smart cavity-coupled electro-rheological fluid sandwich panel

Abstract

The transient vibroacoustic response mitigation of a rectangular sandwich panel with an adaptive electro-rheological fluid core layer, and backed by a hard-walled reverberant rectangular parallelepiped acoustic enclosure, is investigated. The problem is analyzed in a multidisciplinary framework that involves the thin sandwich electro-rheological fluid-based plate model, the 3D wave equation for the acoustic enclosure domain, the first-order Kelvin–Voigt viscoelastic model for the electro-rheological fluid core material, the pertinent structure–fluid compatibility relation, and the inherently robust sliding mode control strategy. The generalized Fourier expansion method is utilized to set up the fully coupled system equations in the state–space domain, and the fourth-order Runge-Kutta time marching technique is then utilized to compute both uncontrolled and controlled coupled system responses in three basic external loading configurations. It is found that increasing the cavity depth has a substantial restraining effect on the overall sound pressure response levels, while the electro-rheological fluid-panel displacement response amplitudes experience only moderate reductions. Also, a purely passive electro-rheological fluid-based system is observed not to be very effective for vibroacoustic response suppression of the cavity-coupled structural system, while the overall success of the applied sliding mode control methodology in reasonable reduction of both panel displacement and sound pressure time response amplitudes is demonstrated. Furthermore, the control system authority with regard to the acoustic cavity pressure (panel displacement) is found to moderately (slightly) decrease as the cavity depth increases. Limiting cases are considered and accuracy of the suggested analytical model is checked against the output of an FEM package as well as with the accessible literature results. Moreover, the main components of a prospective experimental platform for verifying the performance of proposed vibroacoustic control system are briefly described.

Sound transmission control through a hybrid smart double sandwich plate structure

“…The main assumptions/steps for obtaining the governing equations of motion of the simply-supported thin ERF-sandwich plate structure (based on Extended Hamilton’s principle and Kirchhoff's thin plate assumption) are illustrated in literature [12,70]. Accordingly, one can start with the reduced form of equations of motion for the ERF-sandwich panel given as where w1(x,y,t) is the transverse panel displacement, (u0true(1true)(x,y,t),v0true(1true)(x,y,t)) refer to the mid-plane displacement components of the top elastic skin layer in the ( x,y) directions, d=h1+hc, ∇2=∂2∂x2+∂2∂y2,J1=ρ1h1, Jc1=ρchc, Jc2=ρctrue(hctrue)…”

“…Alternatively, employing auxiliary interior sound sources (speakers) for low-frequency sound field cancellation in the active noise control (ANC) technique is rather bulky, intrusive, and expensive, where the structural vibrations essentially continue unaffected [6,7]. On the other hand, the inherent characteristics of smart piezoelectric materials [8–10], electro-rheological fluids (ERFs) [11–13], and magneto-rheological (MR) materials [14,15] directly integrated into the conventional structures as control actuators, along with sophisticated control algorithms and high speed digital computing devices, have made them suitable candidates for active structural acoustic control (ASAC) in distributed parameter systems. Furthermore, by adopting a hybrid design philosophy, one can concurrently benefit from the diverse characteristics of various classes of conventional actuation/absorption mechanisms which cannot be realized by using a single type of actuator/absorber system alone (i.e.…”

“…This will be accomplished, after rigorous development of the associated acousto-elastic model, by applying the computationally simple and intrinsically robust multi-input multi-output sliding mode control (MIMO-SMC) strategy [46–48] to the hybrid smart composite system. This way, the vibroacoustic response of the hybrid structure can effectively be suppressed through smart variation of the damping/stiffness characteristics of the spatially distributed ERF-core layer [11–13] in collaboration with the active uniform force piezoelectric actuator layer [34,49–51] according to the control commands. The proposed acousto-elastic model can be of great interest for sound control engineers seeking acoustic partitions with superior sound transmission loss characteristics [2,6,52].…”

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

“…xh Þ denote the relevant stress and strain components within the elastic skin layers, respectively (see equations (22) and (23) in Appendix 1).…”

“…stiffness and/or damping) in a controlled fashion [16][17][18][19]. The use of tunable electrorheological fluids (ERFs) is a particularly attractive option [20][21][22][23]. These materials can successfully restrain structural resonant peak values in the low and moderate frequency range by undergoing quick and reversible phase transitions when subjected to the control electric field.…”