Predictions of airborne noise between unit cabins by developing a cavity transfer matrix

2021 ◽  
Vol 69 (3) ◽  
pp. 229-242
Author(s):  
Jae-Deok Jung ◽  
Suk-Yoon Hong ◽  
Jee-Hun Song ◽  
Hyun-Wung Kwon
Keyword(s):  
Transfer Matrix ◽  
Sandwich Panel ◽  
Thickness Ratio ◽  
Sound Insulation ◽  
Parameter Study ◽  
The Core ◽  
Airborne Noise ◽  
Core Thickness ◽  
Panel Thickness ◽  
Insulation Performance

The unit cabin has been used to construct internal ship space for improved efficiency and to reduce budgetary costs in shipbuilding. Because the cavity is placed between unit cabins, the noise of one room is transmitted through the sound insulating panel, the cavity, and the opposite sound-insulating panel. In this study, by developing a transfer matrix of the cavity between structures, airborne noise between unit cabins was predicted. A sandwich panel, which is usually used in ships, was employed to construct a double panel, and the sound insulation performance was confirmed by changing the thickness of the cavity. To improve the reliability of numerical results, they were compared with those from experiments conducted. The results showed that as the cavity size increases, the overall sound insulation performance improves. A parameter study was also conducted on the density, Young's modulus, thickness, and thickness ratio of the core of the sandwich panel. To improve the sound insulation performance, increasing the density of the core is preferable to increasing the core thickness. The panel thickness ratio should be increased to avoid performance degradation as a result of the resonance frequency.

Free vibration and buckling analyses of cylindrical sandwich panel with magneto rheological fluid layer

2015 ◽  
Vol 19 (4) ◽  
pp. 397-423 ◽  
Author(s):  
Keramat MalekzadehFard ◽  
Mohsen Gholami ◽  
Farshid Reshadi ◽  
Mostafa livani
Keyword(s):  
Free Vibration ◽  
Sandwich Panel ◽  
Fluid Layer ◽  
Thickness Ratio ◽  
Mode Shapes ◽  
Geometrical Parameters ◽  
Finite Element Software ◽  
Core Thickness ◽  
Magneto Rheological ◽  
Panel Thickness

In this paper, the free vibration and buckling analyses of the cylindrical sandwich panel with magneto-rheological fluid layer for simply supported boundary conditions was performed based on an improved higher order sandwich panel theory. This paper deals with investigation of the effects of magnetic field, geometrical parameters such as the core thickness to the panel thickness ratio, MR layer thickness to the panel thickness ratio and the fiber angle on the natural frequencies, loss factors and buckling loads corresponding to the first four mode shapes. In order to validate the results obtained from the present study, the cylindrical sandwich panel was simulated and analyzed in finite element software ABAQUS. A good agreement was observed between the results of present method and those extracted from simulation.

The buckling of truncated conical sandwich panels under axial compression and external pressure

2014 ◽  
Vol 229 (11) ◽  
pp. 1965-1978 ◽  
Author(s):  
Keramat M Fard ◽  
Mostafa Livani
Keyword(s):  
Boundary Conditions ◽  
Axial Compression ◽  
Sandwich Panel ◽  
Sandwich Panels ◽  
Shear Deformation Theory ◽  
External Pressure ◽  
Thickness Ratio ◽  
Composite Sandwich ◽  
The Core ◽  
Panel Thickness

Based on a new improved higher-order sandwich panel theory, the buckling analysis of a truncated conical composite sandwich panel with simply supported and fully clamped boundary conditions was performed for the first time. This panel was subjected to axial compression and external pressures. The governing equations were derived by using the principle of minimum potential energy. The first-order shear deformation theory was used for the composite face sheets, and for the core, a polynomial description of the displacement fields was assumed. Geometry was used for the consideration of different radii curvatures of the face sheets and the core was unique. The effects of types of boundary conditions, conical angles, length to smaller radius of core ratio, core to panel thickness ratio, and smaller radius of core to panel thickness ratio on the buckling response of truncated conical composite sandwich panels were also studied. The results were validated by the results published in the literature and the presented FE results were obtained by ABAQUS software.

An improved approach for normal-incidence sound transmission loss measurement using a four-microphone impedance tube

2020 ◽  
pp. 107754632092690
Author(s):  
Zechao Li ◽  
Sizhong Chen ◽  
Zhicheng Wu ◽  
Lin Yang
Keyword(s):  
Transfer Matrix ◽  
Sound Absorption ◽  
Transmission Loss ◽  
Sound Transmission ◽  
Normal Incidence ◽  
Sound Insulation ◽  
Sound Transmission Loss ◽  
The Common ◽  
Wavefield Decomposition ◽  
Insulation Performance

The main aim of this study is to introduce an improved method for determining the sound properties of acoustic materials which is more precise than the common wavefield decomposition method and simpler than the common transfer matrix method. In the first part of the article, a group of formulae for calculating sound transmission loss is represented by combining the wavefield decomposition and transfer matrix methods. Subsequently, a formula for calculating sound absorption coefficients is derived from these formulae by definition. Furthermore, the present formulae are validated by comparing the experimental results achieved with the present formulae and those results obtained by other methods recorded in published articles. Eventually, it is demonstrated that the method can accurately measure the sound insulation performance of materials and the sound absorption properties of limp and lightweight materials.

Research on Crushing Performance of Sandwich Panel with V-Type Corrugated Core under Shock Load

2013 ◽  
Vol 694-697 ◽  
pp. 216-220 ◽  
Author(s):  
Lin Chen ◽  
Xiao Zhong Xie ◽  
Zhuo Li ◽  
Ye Qing Jin
Keyword(s):  
Inclination Angle ◽  
Sandwich Structure ◽  
Sandwich Panel ◽  
Structural Parameters ◽  
Design And Optimization ◽  
Finite Element Software ◽  
The Core ◽  
Practical Design ◽  
Core Thickness ◽  
Core Height

Sandwich panels with a V-type corrugated core are developed to investigate their crushing performance under lateral load based on the numerical method. The validity and feasibility of the calculation method is qualified by comparing numerical results with experiment results. Based on that, finite element software is applied to analyze the effects of structural parameters on the crushing performance of sandwich structure. Then inspecific energy increases as the core thickness and inclination angle are increased, but it will induce as the core height is raised. Additionally, the average crushing strength is increased with the increasing thickness, but it will decrease as the core height and inclination angle are raised. The results of this research may help the practical design and optimization of sandwich panel with corrugated core.

Sound Insulation Performance of Finite Orthotropic Sandwich Panels

2013 ◽  
Vol 377 ◽  
pp. 12-16 ◽  
Author(s):  
Sheng Chun Wang ◽  
Wei Dong Shen ◽  
Jia Feng Xu ◽  
Pei Wen Wang ◽  
Yun Li
Keyword(s):  
Transmission Loss ◽  
Sandwich Panels ◽  
Sheet Thickness ◽  
Face Sheet ◽  
Sound Insulation ◽  
Honeycomb Sandwich ◽  
Theoretical Predictions ◽  
Core Thickness ◽  
Insulation Performance ◽  
Good Agreement

A theoretical model for calculating sound transmission loss (STL) of finite honeycomb sandwich panels is developed. The accuracy of the theoretical predictions is checked against experimental data, with good agreement achieved. Numerical analysis shows that increasing face sheet thickness can improve STL effectively, which is much more effective than increasing the core thickness. Core thickness and Youngs modulus of face sheet have evident effect on coincidence frequency, which should not be neglected when predicting STL.

Characteristics of Truss Core Created by Origami Forming Method

2019 ◽  
Author(s):  
Aya Abe ◽  
Kosuke Terada ◽  
Haruki Yashiro ◽  
Ichiro Hagiwara
Keyword(s):  
Sound Insulation ◽  
Honeycomb Core ◽  
Bending Tests ◽  
Three Point Bending ◽  
Mountain Valley ◽  
The Core ◽  
Truss Core ◽  
Drop Tests ◽  
Insulation Performance ◽  
Cushioning Material

Abstract The truss core surpasses the honeycomb core depending on the tasks. The height of core is limited by press forming and so on. Therefore, we developed a method by folding mountain / valley lines like origami. The origami forming method has the feature that it can be done from paper to metal by the same method. By examining three-point bending tests, drop tests, and analyzing them, we show that the structure that space-filled with cores obtained by the origami forming method called ATCP will be a box for both excellent cushioning material and transporting. Moreover, we also show that the core structure obtained by this has excellent sound insulation performance.

AXISYMMETRIC SIMULATION OF BULGING PROCESS IN POLYMERIC MATERIALS DURING PROJECTILE IMPACT

2008 ◽  
Vol 22 (09n11) ◽  
pp. 1598-1603
Author(s):  
KYUNG-HUN LIM ◽  
SEE-JO KIM ◽  
HYUNG-SEOP SHIN ◽  
JOON-HONG CHOI ◽  
JEONG-TAE KIM
Keyword(s):  
Sandwich Panel ◽  
Polymeric Materials ◽  
Projectile Impact ◽  
Material Parameters ◽  
The Core ◽  
Elapsed Time ◽  
Core Thickness ◽  
Impact Problems ◽  
Materials Used ◽  
Axisymmetric Impact

Combination of different materials used both in the projectile and the sandwich panel is getting more important in designing for maximization of energy absorption during impact. In the present study, we have simulated the bulging process during projectile impact for axisymmetric impact problems. We have discussed the bulging velocity tendency depending on some important geometrical and material parameters such as the yield strength, and tensile limit of the core for several different core thickness and different elapsed time after impact by using the AUTODYN commercial software. From our simulation, we have found that material properties have more dominant effects than the geometric properties on the bulging velocity.

Effect of Core Thickness on Load Carrying Capacity of Sandwich Panel Behavior Beyond Yield Limit

2011 ◽  
pp. 171-181
Author(s):  
Salih N. Akour ◽  
Hussein Maaitah ◽  
Jamal F. Nayfeh
Keyword(s):  
Experimental Investigation ◽  
Finite Element ◽  
Carrying Capacity ◽  
Sandwich Panel ◽  
Core Material ◽  
Load Carrying Capacity ◽  
Yield Limit ◽  
The Core ◽  
Load Carrying ◽  
Core Thickness

Sandwich Panel has attracted designer’s interest due to its light weight, excellent corrosion characteristics and rapid installation capabilities. It has been implemented in many industrial application such as aerospace, marine, architectural and transportation industry. Its structure consists of two face sheets and core. The core is usually made of material softer than the face sheets. The current investigation unveils the effect of core thickness on the behavior of Sandwich Panel beyond the yield limit of core material. The core thickness is investigated by utilizing univariate search optimization technique. The load is applied in quasi–static manner (in steps) till face sheets reach the yield limit. Simply supported panel from all sides is modeled using a finite element analysis package. The model is validated against numerical and experimental cases that are available in the literature. In addition, experimental investigation has been carried out to validate the finite element model and to verify some selected cases. The finite element results show very good agreement with the previous work and the experimental investigation. The study presents that the load carrying capacity of the panel increases as the core material goes beyond the yield point. Also, increasing core thickness to a certain limit delays the occurrence of core yielding and gives opportunity to face sheets to yield first.

scholarly journals A numerical study of the impact perforation of sandwich panels with graded hollow sphere cores

2021 ◽  
Vol 13 (4) ◽  
pp. 168781402110094
Author(s):  
Ibrahim Elnasri ◽  
Han Zhao
Keyword(s):  
Boundary Conditions ◽  
Hollow Sphere ◽  
Sandwich Panel ◽  
Numerical Study ◽  
Sandwich Panels ◽  
Hopkinson Bar ◽  
Core Density ◽  
The Core ◽  
The Impact ◽  
Force Displacement

In this study, we numerically investigate the impact perforation of sandwich panels made of 0.8 mm 2024-T3 aluminum alloy skin sheets and graded polymeric hollow sphere cores with four different gradient profiles. A suitable numerical model was conducted using the LS-DYNA code, calibrated with an inverse perforation test, instrumented with a Hopkinson bar, and validated using experimental data from the literature. Moreover, the effects of quasi-static loading, landing rates, and boundary conditions on the perforation resistance of the studied graded core sandwich panels were discussed. The simulation results showed that the piercing force–displacement response of the graded core sandwich panels is affected by the core density gradient profiles. Besides, the energy absorption capability can be effectively enhanced by modifying the arrangement of the core layers with unclumping boundary conditions in the graded core sandwich panel, which is rather too hard to achieve with clumping boundary conditions.

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