© Copyright Our Wall
Sound Insulation of Corrugated-Core Sandwich Panels
With the extension of the applications of sandwich panels with corrugated core, sound insulation performance has been a great concern for acoustic comfort design in many industrial fields. This paper presents a numerical and experimental study on the vibro-acoustic optimization of a finite size sandwich panel with corrugated core for maximizing the sound transmission loss. The numerical model is established by using the wave-based method, which shows a great improvement in the computational efficiency comparing to the finite element method. Constrained by the fundamental frequency and total mass, the optimization is performed by using a genetic algorithm in three different frequency bands. According to the optimization results, the frequency averaged sound transmission of the optimized models in the low, middle, and high-frequency ranges has increased, respectively, by 7.6 dB, 7.9 dB, and 11.7 dB compared to the baseline model. Benefiting from the vast number of the evolution samples, the correlation between the structural design parameters and the sound transmission characteristics is analyzed by introducing the coefficient of determination, which gives the variation of the importance of each design parameter in different frequency ranges. Finally, for validation purposes, a sound insulation test is conducted to validate the optimization results in the high-frequency range, which proves the feasibility of the optimization method in the practical engineering design of the sandwich panel.Get more news about Bh-sandwich Panel Series,you can vist our website!
Because of its high stiffness to mass ratio and excellent impact resistance property, lightweight sandwich panels are largely used in civil construction, high-speed vehicle, ship structure, and aerospace industries [1,2]. A typical sandwich panel usually consists of two face sheets and a core layer. According to the different types of the core, sandwich panels can be broadly separated into two categories, homogeneous core sandwich panels and non-homogeneous (structure supported) core sandwich panels. Due to the lack of mechanical strength, the former type (e.g., foam core sandwich panel) is commonly used in the applications under light load condition. To overcome this drawback, the latter type, non-homogeneous sandwich panel, uses structural stiffener as the core layer. The core structure not only provides additional mechanical strength and bending stiffness but can also keep the lightweight characteristics of the sandwich panel. With the extension of the applications of sandwich panels, the vibro-acoustic properties, especially the sound insulation performance, have attracted great attention for acoustic comfort design in many industrial fields [3].
Due to the geometry diversity of the structural core, the mechanism of sound transmission through structure supported sandwich plate is complicated. Under this circumstance, many theoretical models were proposed to study the basic vibro-acoustic behaviors of structure supported sandwich plate. In the early stage, beginning with investigating sound transmission through building element, Sharp [4] studied the sound insulation performances of structure reinforced double wall structure and proposed an analytical model to predict the sound transmission loss. In this model, the structural reinforcement was assumed as totally rigid, and the link impedance was introduced to evaluate the sound transmission via structural path. Fahy [5] calculated the sound reduction index of double-leaf partitions with timber and steel studs based on the same rigid assumption. The comparison between the calculated results and experimental data indicated that this highly idealized theoretical model works well when the two face sheets are linked by inelastic studs.
As for the elastic structure linked sandwich plates, Brunskog [6] presented a deterministic prediction model for airborne sound insulation performances of an infinite double leaf structure. In his study, both the structural and acoustical (acoustic cavities) sound transmission paths are considered. However, as a simplification, the periodically placed orthogonal studs were treated as bar-like beams, and only the axial displacement was considered. Taking the flexural vibration of structural stiffeners into consideration, Xin and Lu [7] proposed an analytical model to evaluate the sound transmission of lightweight all-metallic sandwich panels. In their study, the structural stiffeners were simplified as translational and rotational springs with concentrated mass. Meanwhile, the structural–acoustical coupling effect was assumed to take place only between the acoustic cavity and the two face sheets. The results indicated that the core geometry exerts a significant effect on the sound insulation performance of the sandwich plate.
The Wall