A review on optimization of composite structures Part II: Functionally graded materials

This paper reviews the most of previous works through vibroacoustic performance of shell structures in past years (1957–2019). The major end is especially placed to collate the researches carried out in the area of power transmission through shell structures during the last 60 years. For this purpose, a series of categories are first highlighted in order to classify the issues that should be searched. The review is then directed with emphasis on the kinds of shells with different geometries containing cylindrical and doubly curved shells. Later on, not only a popular discussion is proposed to model the acoustic behavior of shells based on the different theories (classical, shear deformation and three-dimensional) but also a perfect explanation is provided wherein the importance of modeling the structures according to the different materials is revealed. To extend the review, various boundary conditions (finite and infinite) are also investigated. Besides, the further effects of external environments as fluid and thermal are inspected. Since the type of incident field can be impressive on the sound insulation specification of these shells, the structure is characterized based on the various acoustic excitations involving plane wave and point source incidences. Furthermore, some descriptions on the solution procedures (analytical, experimental and numerical) are also given. As a result, the review is centralized through other matters such as control and optimization techniques in order to improve the vibroacoustic behavior of shell structures.

Acoustic Insulation Characteristics of Shell Structures: A Review

Vibroacoustic study on a multilayered functionally graded cylindrical shell with poroelastic core and bonded-unbonded configuration

The increasing motivation behind the recently wide industrial applications of sandwich and composite double panel structures stems from their ability to absorb sounds more effectively. Meticulous selection of the geometrical and material constituents of both the core and panels of these structures can produce highly desirable properties. A good understanding of their vibro-acoustic response and emission index such as the sound transmission loss (STL) is, therefore, a requisite to producing optimal design. In this study, an overview of recent advances in STL of sandwich and composites double panels is presented. At first, some salient explanation of the various frequency and controlled regions are given. It then critically examines a number of parameter effects on the STL of sandwich and composite structures. Literatures on the numerical, analytical and experimental solutions of STL are systematically presented. Efficient and more reliable optimization problems that maximize the STL and minimize the objective functions capable of degrading the effectiveness of the structure to absorb sounds are also provided.

https://www.mdpi.com/2076-3417/10/4/1543/pdf

Comparative Study of Sound Transmission Losses of Sandwich Composite Double Panel Walls

The active damping control strategy upgraded by a multi-objective particle swarm optimization algorithm is utilized for improved broadband suppression of sound transmission through a simply support...

Broadband sound transmission loss enhancement of an arbitrary-thick hybrid smart composite plate using multi-objective particle swarm optimization–based active control:

The maximizing of sound transmission loss (TL) across a functionally graded material (FGM) cylindrical shell has been conducted using a genetic algorithm (GA). To prevent the softening effect from occurring due to optimization, the objective function is modified based on the first resonant frequency. Optimization is performed over the frequency range 1000–4000 Hz, where the ear is the most sensitive. The weighting constants are chosen here to correspond to an A-weighting scale. Since the weight of the shell structure is an important concern in most applications, the weight of the optimized structure is constrained. Several traditional materials are used and the result shows that optimized shells with aluminum-nickel and aluminum-steel FGM are the most effective at maximizing TL at both stiffness and mass control region, while they have minimum weight.

/pdf/optimization-of-sound-transmission-loss-through-a-thin-21qwuw3cv2.pdf

Sohrab Astaraki

Papers

Optimization of Sound Transmission Loss through a Thin Functionally Graded Material Cylindrical Shell