Metamaterial foam core sandwich panel designed to attenuate the mass-spring-mass resonance sound transmission loss dip

2020 ◽  
Vol 139 ◽  
pp. 106624 ◽  
Author(s):  
N.G.R. de Melo Filho ◽  
C. Claeys ◽  
E. Deckers ◽  
W. Desmet
2013 ◽  
Vol 135 (6) ◽  
Author(s):  
Zhongchang Qian ◽  
Daoqing Chang ◽  
Bilong Liu ◽  
Ke Liu

An approach on the prediction of sound transmission loss for a finite sandwich panel with honeycomb core is described in the paper. The sandwich panel is treated as orthotropic and the apparent bending stiffness in two principal directions is estimated by means of simple tests on beam elements cut from the sandwich panel. Utilizing orthotropic panel theory, together with the obtained bending stiffness in two directions, the sound transmission loss of simply-supported sandwich panel is predicted by the modal expansion method. Simulation results indicated that dimension, orthotropy, and loss factor may play important roles on sound transmission loss of sandwich panel. The predicted transmission loss is compared with measured data and the agreement is reasonable. This approach may provide an efficient tool to predict the sound transmission loss of finite sandwich panels.


2019 ◽  
Vol 86 ◽  
pp. 714-723 ◽  
Author(s):  
Tao Fu ◽  
Zhaobo Chen ◽  
Hongying Yu ◽  
Xuezhi Zhu ◽  
Yanzheng Zhao

2017 ◽  
Vol 9 (7) ◽  
pp. 168781401771394 ◽  
Author(s):  
Qibo Mao ◽  
Hui Shen

It is well-known that the acoustic performance of double-plate structures deteriorates rapidly around the mass–air–mass resonance frequency. In this study, a mass–spring–damper system connected between incident and radiating plates is used to improve the sound transmission loss at low-frequency ranges. First, a full structural-acoustic modal coupling model is developed to analyze the vibration and acoustical behaviour of the double-plate structures with mass–spring–damper system. Because there are in-phase or out-of-phase vibrations between double plates, tuning the natural frequency of the mass–spring–damper system exactly to the mass–air–mass resonance frequency cannot guarantee the maximum improvement on transmission loss. Optimal natural frequency and mass of the mass–spring–damper system were found as a solution of optimization problem with a global cost function defined as frequency-averaged sound transmission loss in the desired frequency range (around mass–air–mass resonance frequency). Finally, some numerical calculation results are presented. The calculated results show that the sound transmission loss of a double-plate structure can be improved significantly using optimally tuned mass–spring–damper system. The results indicate that an overall improvement of 12 dB below 1000 Hz can be achieved when the mass of the mass–spring–damper system equals to 10% weight of the double-plate structure.


2020 ◽  
Vol 54 (2) ◽  
pp. 127-137
Author(s):  
Rohollah Fallah Madvari ◽  
Mohammad Reza Monazzam ◽  
Mohsen Niknam Sharak and Mohsen Mosa Farkhani

2016 ◽  
Vol 19 (1) ◽  
pp. 26-48 ◽  
Author(s):  
MP Arunkumar ◽  
Jeyaraj Pitchaimani ◽  
KV Gangadharan ◽  
MC Lenin Babu

Sandwich panel which has a design involving acoustic comfort is always denser and larger in size than the design involving mechanical strength. The respective short come can be solved by exploring the impact of core geometry on sound transmission characteristics of sandwich panels. In this aspect, the present work focuses on the study of influence of core geometry on sound transmission characteristics of sandwich panels which are commonly used as aircraft structures. Numerical investigation has been carried out based on a 2D model with equivalent elastic properties. The present study has found that, for a honeycomb core sandwich panel in due consideration to space constraint, better sound transmission characteristics can be achieved with lower core height. It is observed that, for a honeycomb core sandwich panel, one can select cell size as the parameter to reduce the weight with out affecting the sound transmission loss. Triangular core sandwich panel can be used for low frequency application due to its increased transmission loss. In foam core sandwich panel, it is noticed that the effect of face sheet material on sound transmission loss is significant and this can be controlled by varying the density of foam.


2019 ◽  
Vol 9 (7) ◽  
pp. 1276 ◽  
Author(s):  
Massimo Fortini ◽  
Nicola Granzotto ◽  
Edoardo Piana

Composite panels are being increasingly used in many applications because they can combine several interesting properties, such as high load-bearing capacity, low weight, and excellent thermal insulation. Different core materials can be used for composite sandwich panels, like polystyrene, mineral wool, polyurethane, glass wool, or rigid phenolic foam, which is considered the rigid plastic foam with the best fire-proof properties. During the research and development phase, the use of simulation tools is often required for the improvement of the mechanical behavior of the material. The aim of the paper is to characterize some vibro-acoustic parameters of a sandwich material with phenolic open-cell foam core. The sound transmission loss of the structure is calculated based on its flexural behavior, represented through a frequency-dependent “apparent” bending stiffness which is estimated by natural frequency vibration tests on beam specimens. The comparison between sound transmission loss predictions and measurements in sound transmission suites according to ISO 10140-2 is presented and discussed. Finally, the early-stage prediction potentiality of the mathematical model is investigated when only nominal information is available on the constituent layers, showing that particular attention should be paid to the modifications introduced by the manufacturing process.


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