scholarly journals Investigating the Effect of Dimension Parameters on Sound Transmission Losses in Nomex Honeycomb Sandwich

2020 ◽  
Vol 10 (9) ◽  
pp. 3109 ◽  
Author(s):  
Da Wang ◽  
Suchao Xie ◽  
Zhejun Feng ◽  
Xiang Liu ◽  
Yingli Li
Keyword(s):  
High Frequency ◽  
Transmission Loss ◽  
Sound Transmission ◽  
Layered Structures ◽  
Test Method ◽  
Core Material ◽  
Impedance Tube ◽  
Tube Test ◽  
Honeycomb Sandwich ◽  
Nomex Honeycomb

In this study, an impedance tube test was performed to explore the influence of various dimension parameters of Nomex honeycomb sandwich core material on sound transmission loss (STL). The parameters investigated included the size of the honeycomb cells and thickness of the face sheets and honeycomb cores, and the effects of single- and double-layered sandwich structures were also explored. The boundary element and finite element methods were used to simulate test results. The results show that the size of the honeycomb cells has an insignificant effect on STL. Increasing the thickness of face sheets can move the STL valley point of the material at high frequency (around 5 kHz) in the low-frequency direction and increase the STL in parts of the high frequency band. Increasing the thickness of the honeycomb core can improve STL, on the whole, but the magnitude of the improvement effect becomes weakened after the thickness of the core reaches 30 mm. The STL of double-layered structures was found to be superior to that of the single-layered structures. The simulations reveal that the trends in the STL curves of the honeycomb sandwich panels are influenced by the structural mode of the panels, and are related to the resonance of the materials. The results and relevant conclusions obtained through the above research verify that the law of influence of the structure dimension parameters on the STL measured by the impedance tube is similar to that of the large panel. This can provide a reference for the application of the impedance tube test method in structural noise reduction design.

Advanced Low Df Dry film Build-up Material on Glass panel for 5G application

2020 ◽  
Vol 2020 (1) ◽  
pp. 000201-000205
Author(s):  
Takenori Kakutani ◽  
Zhong Guan ◽  
Yuya Suzuki ◽  
Muhammad Ali ◽  
Serhat Erdogan ◽  
...  
Keyword(s):  
High Frequency ◽  
Transmission Loss ◽  
Core Material ◽  
Wave Band ◽  
Organic Substrates ◽  
Frequency Filter ◽  
Transmission Characteristics ◽  
Glass Panel ◽  
Low Loss ◽  
Dry Film

Abstract This paper describes the demonstration of a low loss substrate (laminated glass) for high-frequency transmission using a dry film build-up material with low loss tangent (Df). This paper also evaluates filter characteristics and dielectric characteristics of the substrate in the mm-Wave band. The advanced low loss dry film build-up material was newly developed, and applicable to high frequency transmission. This material has a Df of 0.0025 at 10 GHz and also exhibits excellent adhesion and electrical reliability required for advanced dielectric materials. In addition, glass was used as a core material in this paper because of its excellent signal transmission characteristics compared to silicon wafers or organic substrates. To demonstrate the benefit of low loss materials for high frequency transmission, passive components for high frequency filter substrates were fabricated using - 6-inch square thin (0.2mm) glass panel with various build-up materials (Material A with a Df of 0.0025, and Material B with a Df 0.0042 at 10 GHz) laminated. Copper wiring patterns on the dielectric layers were fabricated by a semi-additive process (SAP). Circuit patterns with low pass filters and band pass filters were also fabricated. First, transmission characteristics and characteristic impedances were measured to check the electrical performance. The measured lowest transmission loss of < 1.43 dB at 39 GHz were achieved when Material A was applied as the build-up material. Second, biased-highly accelerated stress test (bHAST) was conducted to evaluate the reliability performance of the substrates with two build-up materials, Material A and a conventional material. The test condition was based on the JEDEC level 2 standard. The substrate with Material A retained good insulation properties over 300 hours of bHAST treatment, demonstrating its excellent insulating performance. In summary, Material A has been shown in this paper to exhibit reduced transmission loss in high-frequency filter substrates at millimeter wave frequencies.

Quasi-Static Failure Analysis of Honeycomb Sandwich Beam with Composite Facesheets

2010 ◽  
Vol 160-162 ◽  
pp. 855-859 ◽  
Author(s):  
Li Qing Meng ◽  
Yan Wu ◽  
Shi Zhe Chen ◽  
Xue Feng Shu
Keyword(s):  
Sandwich Beam ◽  
Indentation Test ◽  
Core Material ◽  
Honeycomb Core ◽  
Three Point Bending ◽  
Composite Sandwich ◽  
Sandwich Construction ◽  
Honeycomb Sandwich ◽  
Nomex Honeycomb ◽  
Static Failure

Sandwich construction consists of two thin composite or metal facesheets separated by a core material. Despite extensive researches on the sandwich constructions, their mechanical properties and failure behaviours are still not fully understand. The objective of the paper is to use a experimental and theoretical predicting failure mode for sandwich beam consisting of GFRP facesheets and Nomex honeycomb core. Two kinds of composite sandwich beams are observed in quasi-static three-point bending and indentation test.

scholarly journals Analytical Study on the Rate of Sound Transmission Loss in Single Row Honeycomb Sandwich Panel Using a Numerical Method

2020 ◽  
Vol 54 (2) ◽  
pp. 127-137
Author(s):  
Rohollah Fallah Madvari ◽  
Mohammad Reza Monazzam ◽  
Mohsen Niknam Sharak and Mohsen Mosa Farkhani
Keyword(s):  
Numerical Method ◽  
Analytical Study ◽  
Sandwich Panel ◽  
Transmission Loss ◽  
Sound Transmission ◽  
Sound Transmission Loss ◽  
Single Row ◽  
Honeycomb Sandwich

scholarly journals Analytical Expression for Sound Transmission Loss Calculation: An Improvement to the Existing Method after Singh and Katra

2009 ◽  
Vol 2009 ◽  
pp. 1-3
Author(s):  
Iwan Yahya
Keyword(s):  
Sound Source ◽  
Spectral Decomposition ◽  
Transmission Loss ◽  
Sound Transmission ◽  
Test Sample ◽  
Sound Transmission Loss ◽  
Impedance Tube ◽  
Analytical Expression ◽  
Time Signals ◽  
Short Time

An analytical expression for measuring of sound transmission loss (TL) has been developed by using two microphones, an impedance tube and an impulse sound source as a proposed improvement to the existing procedure after Singh and Katra (1978). The calculation procedure is based on the autospectrum of short-time signals captured by the two microphones placed on two opposite positions from test sample while the sound source is on its surface. No spectral decomposition is required and the TL is calculated directly from the autospectrums of captured signals.

scholarly journals Sound Insulation of Corrugated-Core Sandwich Panels: Modeling, Optimization and Experiment

Materials ◽  
2021 ◽  
Vol 14 (24) ◽  
pp. 7785
Author(s):  
Longlong Ren ◽  
Haosen Yang ◽  
Lei Liu ◽  
Chuanlong Zhai ◽  
Yuepeng Song
Keyword(s):  
High Frequency ◽  
Sandwich Panel ◽  
Transmission Loss ◽  
Finite Size ◽  
Sandwich Panels ◽  
Sound Transmission ◽  
Coefficient Of Determination ◽  
Design Parameters ◽  
Sound Insulation ◽  
Vast Number

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.

Sign in / Sign up

Export Citation Format

Share Document