Acoustic performance prediction of a multilayered finite cylinder equipped with porous foam media

Abstract

This paper presents an analytical model to embed porous materials in a finite cylindrical shell in order to obtain the sound transmission loss coefficient. Although the circumferential modes are considered only for calculating the amount of the transmitted noise through an infinitely long cylinder, the present study employs the longitudinal modes in addition to circumferential ones to analyze the vibroacoustic performance of a simply supported cylinder subjected to the porous core based on the first order shear deformation theory. To achieve this goal, the structure is immersed in a fluid and excited by an acoustic wave. In addition, the acoustic pressures and the displacements are developed in the form of double Fourier series. Since these series consist of infinite modes, it is essential to terminate this process by considering adequate modes. Hence, the convergence checking algorithm is employed in the form of some three-dimensional configurations with respect to length, frequency and radius. Afterwards, some figures are plotted to confirm the accuracy of the present formulation. In these configurations, the obtained sound transmission loss from the present study is compared with that of the infinite one. It is shown that by increasing the length of the structure, the results are approached to sound transmission loss of the infinite shells. Moreover, a new approach is proposed to show the transverse displacement of a finite poroelastic cylinder at different frequencies. Based on the outcomes, it is found that by enhancing the length of the poroelastic cylinder, the amount of the transmitted sound into the structure is reduced at the high frequency domain. However, the sound insulation property of the structure is improved at the low frequency region when the radius of the shell is decreased.

Prediction of acoustic wave transmission features of the multilayered plate constructions: A review

“…Tsai et al. [11] 0 estimated and optimized the material characteristics of a composite plate to calculate the STL of a structure according to conjugate gradient optimization using thick plate theory. Additionally, the numerical simulations were provided by evaluating the acoustic transmission of the optimal structure compared to the principal one.…”

“…Cherif et al. [11] 1 specified the STL curve of a sandwich panel based on the measurement data. According to the results, the acoustic characteristic of the used structure was exactly evaluated and compared well with that of equivalent one.…”

“…Another unique feature of these structures is that by adapting the geometric and material factors of the skins and core, it is possible to optimally create some different designs for specific usages while the primary intention is to attenuate the value of noise transmitted into the construction. Multilayered structures can be modeled in the form of a plate [1], doubly curved shell [2–6], and cylindrical shell [7–11]. It is noteworthy that plate structures [12,13] do not involve any radii of curvature.…”

Measurement Interface Stiffness of Bonded Structures Using Air-Coupled Ultrasonic Transmission Technology

“…Laminated composite structures are widely used in aircraft engine shroud and wing spoiler, solid rocket motor casing, missile launcher canister due to its high specific strength, high specific modulus, superior shock absorption, fatigue resistance, and simple manufacture technology [1][2][3]. Thus, research on the acoustic characteristics of sandwich or interface of composite structures has always been the focus of attention, which is used to design the materials and properties of interface layer [4,5]. Bonded structure is one of the most common forms of composite materials, and its interface failure caused by insufficient stiffness from the bonding layer occurs frequently and even leads to accidents.…”

Damage Propagation Prediction of Adhesion Failure in Composite T-joint Structure and Improvement using PZT Patch

“…Therefore, it is very much important to identify the exact failure location and provide resistance to the propagation of failure. Laminated composite structures gained a large amount of attention among researchers because of their wide range of applications in vital research fields [1][2][3][4][5][6][7][8][9][10][11]. The mechanical and electric properties of these laminated composite structures can be further enhanced by attaching smart piezoelectric layers and combinedly they form a smart laminated composite structure.…”