VIBRO-ACOUSTIC BEHAVIORS OF FLAT SANDWICH COMPOSITE PANELS

2006 ◽  
Vol 30 (4) ◽  
pp. 473-493 ◽  
Author(s):  
Sebastian Ghinet ◽  
Noureddine Atalla
Keyword(s):  
Laminate Composite ◽  
Transmission Loss ◽  
Order Relation ◽  
Dispersion Relations ◽  
Composite Panel ◽  
Sandwich Composite ◽  
Composite Panels ◽  
Low Frequencies ◽  
Total Transmission ◽  
Modal Density

The main objective of this paper is to present a theoretical approach to model the vibro-acoustic behavior of flat sandwich composite panels. Two models are studied: symmetrical laminate composite and sandwich composite panel. The theories are developed in a wave approach context. It is shown that a discrete layers sandwich composite panel modeling type leads to a 12th order relation of dispersion while a laminate composite panel modeling leads to a 6th order relation of dispersion. The two models give similar results at low frequencies but the modeling of a sandwich panel using the laminate panel theory leads to inaccuracies at high frequencies. The dispersion relations are first solved in the context of generalized polynomial complex eigenvalues problems. Next, the dispersion relations are used to derive the analytical expression of the critical frequencies and to calculate the natural frequencies of the panel. Using the dispersion relation’s solutions, the study is then focused on the numerical computation of the group velocity, the modal density and the total transmission loss.

scholarly journals Research and practices of large composite external wall panels for energy saving prefabricated buildings

2019 ◽  
Vol 289 ◽  
pp. 10012
Author(s):  
Yunxing Shi ◽  
Yangang Zhang ◽  
Kun Ni ◽  
Wei Liu ◽  
Ye Luo
Keyword(s):  
Production Process ◽  
Energy Saving ◽  
Thermal Insulation ◽  
Sandwich Panel ◽  
Composite Panel ◽  
Sandwich Composite ◽  
Composite Panels ◽  
Load Bearing ◽  
External Wall ◽  
Wall Panels

The production process and application of large composite external wall panels (composite panels for short) are introduced in this paper. Composite panels with both load bearing and thermal insulation were formed by pouring normal concrete (NC) and ceramsite foamed concrete (CFC) continuously according to particular technological requirements, which made two layers into a seamless whole. The layers of NC and CFC are for load bearing and thermal insulation respectively. The composite panels were manufactured in the scale of industrial production, and applied to several energy saving prefabricated buildings successively, instead of polystyrene sandwich composite panels (sandwich panel for short) as external wall panels. There are several obvious advantages of the composite panel over the sandwich panel or outer benzoic board. Firstly, it solved the problems of durability of polystyrene and the complex production process of the sandwich pane, the production process of the external wall was thus greatly simplified. In addition, the fire risk was much reduced.

On the Variability of the Sound Transmission Loss of Composite Panels Through a Parametric Probabilistic Approach

2016 ◽  
Vol 24 (01) ◽  
pp. 1550018 ◽  
Author(s):  
M. A. Ben Souf ◽  
D. Chronopoulos ◽  
M. Ichchou ◽  
O. Bareille ◽  
M. Haddar
Keyword(s):  
Transmission Loss ◽  
Probabilistic Approach ◽  
Sound Transmission ◽  
Wave Mode ◽  
Composite Panel ◽  
Mode Shapes ◽  
Composite Panels ◽  
Sound Transmission Loss ◽  
Acoustic Response ◽  
Polynomial Eigenvalue Problem

A robust model for the prediction of the variability of the vibro-acoustic response is presented in this paper. The dynamic response of composite panels is treated using a Statistical Energy Analysis (SEA) approach. One of the basic input parameters is the propagating flexural wavenumber of the modeled panel. The Wave Finite Element Method (WFEM) is used to investigate the dispersion characteristics of the layered panel. It is based on the evaluation of the mass and the stiffness matrices of a periodic segment of the structure. A polynomial eigenvalue problem is then formed for calculating the wavenumbers and the wave mode shapes. The main novelty in this paper consists in evaluating the influence of the variability of the mechanical parameters of the composite panel on its vibro-acoustic response, that is on its sound transmission loss (STL). This influence is quantified using the generalized polynomial chaos expansion. The efficiency of the approach is exhibited for isotropic and orthotropic panels.

scholarly journals Numerical Simulation of Damage in Sandwich Composite Panels Due to Hydrodynamic Impact

2021 ◽  
Vol 53 (3) ◽  
pp. 210304
Author(s):  
Satrio Wicaksono ◽  
Nur Ridhwan Muharram ◽  
Hermawan Judawisastra ◽  
Tatacipta Dirgantara
Keyword(s):  
Numerical Simulation ◽  
Numerical Study ◽  
Fluid Motion ◽  
Real Life ◽  
Damage Mechanism ◽  
Composite Panel ◽  
Sandwich Composite ◽  
Composite Panels ◽  
Hydrodynamic Load ◽  
Hydrodynamic Impact

The float and hull are vital parts of amphibious planes and boats, respectively, as both have to absorb hydrodynamic impact due to interaction with water. Sandwich composite panels are commonly used for such applications and other impact-absorbing structures. Unfortunately, the failure mechanism of sandwich composite panels under hydrodynamic impact is very complicated, as it may consist of composite skin failure, core failure, and non-uniform delamination. Hence, a numerical study on the damage of sandwich composite panels under hydrodynamic load is necessary. In this study, numerical simulation implementing the Coupled Eulerian-Lagrangian (CEL) method was performed to observe the damage mechanism of sandwich composite panels. The CEL method combines the Lagrangian and Eulerian frames into one model. Thus, analysis of structure deformation and fluid motion can be performed simultaneously. The result of the current numerical simulation shows a fair agreement with the experimental results in the literature, which shows that the current methodology can represent the sandwich composite panel response in real-life conditions, especially before shear core failure initiates.

Underwater Impulsive Loading-Induced Dynamic Failures of Monolithic Composite Panel

2014 ◽  
Vol 553 ◽  
pp. 539-544 ◽  
Author(s):  
Phuong Tran ◽  
Tuan D. Ngo ◽  
Priyan Mendis
Keyword(s):  
Strain Rate ◽  
Sandwich Panels ◽  
Interaction Model ◽  
Unidirectional Composite ◽  
Impulsive Loading ◽  
Composite Panel ◽  
Sandwich Composite ◽  
Composite Panels ◽  
Cohesive Law ◽  
Deformation And Failure

Designing light-weight high-performance materials which can sustain high impulsive loadings is of great interest to marine applications. In this study, a finite element fluid-structure interaction model is developed to understand the deformation and failure mechanisms of both monolithic and sandwich composite panels. Fiber (E-glass fiber) and matrix (vinylester resin) damage and degradation in individual unidirectional composite laminas are modeled with Hashin’s model. The delamination between laminas is modeled by developing a strain rate sensitive cohesive law. The deformation of the core (H250 PVC foam) in sandwich panels is modelled as a crushable foam plasticity model with volumetric hardening and strain rate sensitivity as well. The deformation history, fiber/matrix damage patterns in laminas, and inter-lamina delamination in both monolithic and sandwich composite panels are identified and compared with the experimental observations. The model suggests that the foam plays an important role in improving the performance of the sandwich panels by suppressing the transmitted impulsive acting on the back-sheets.

The transmission loss of curved laminates and sandwich composite panels

2005 ◽  
Vol 118 (2) ◽  
pp. 774-790 ◽  
Author(s):  
Sebastian Ghinet ◽  
Noureddine Atalla ◽  
Haisam Osman
Keyword(s):  
Transmission Loss ◽  
Sandwich Composite ◽  
Composite Panels

scholarly journals Development of lignocellulosic fiber reinforced cement composite panels using semi-dry technology

Cellulose ◽  
2021 ◽  
Vol 28 (6) ◽  
pp. 3631-3645
Author(s):  
K. M. Faridul Hasan ◽  
Péter György Horváth ◽  
Tibor Alpár
Keyword(s):  
Flexural Modulus ◽  
Cement Composite ◽  
Composite Panel ◽  
Bending Test ◽  
Morphological Properties ◽  
Cement Stone ◽  
Composite Panels ◽  
Internal Bonding ◽  
Dry Process ◽  
Lignocellulosic Fiber

AbstractThere is a growing interest in developing cement bonded lignocellulosic fiber (LF) composites with enhanced mechanical performances. This study assessed the possibility of developing composite panels with 12 mm thickness and around 1200 kg/m3 nominal densities from ordinary Portland cements (OPC) and mixed LFs from seven different woody plants found in Hungary. Once the mixed LFs were sieved and found fine (0–0.6 mm) and medium (0.6–0.8 mm) length fibers. The optimum ratio for LF, OPC, water glass (Na2SiO3), and cement stone was found to be 1:3.5:0.7:0.07. The semi-dry process, which is a comparatively cheaper and less labor intensive technology, was used for producing the composites. After 28 days of curing, the composite panels were characterized for mechanical, physical, thermal, and morphological properties. A scanning electron microscopy (SEM) test was conducted to observe the fiber orientation in the matrix before and after the bending test, which showed the clear presence of the fibers in the composites. The FTIR (Fourier transform infrared spectroscopy) was conducted to investigate the presence of chemical compounds of LF in the composite panels. Different physical (water absorption and thickness swelling) characteristics of the composite panels were investigated. Furthermore, mechanical properties (flexural properties and internal bonding strength) of the composite panels were also found to be satisfactory. The flexural modulus and internal bonding strengths of composite panel 2 is higher than other three boards, although the flexural strength is a little lower than composite panel 1. The thermogravimetric analysis and differential thermogravimetry also indicated better thermal stability of composite panels which could be used as potential insulation panel for buildings. Graphic abstract

scholarly journals Characterization and ballistic performance of thin pre-damaged resin-starved aramid-fiber composite panels

2021 ◽  
pp. 004051752110134
Author(s):  
Cerise A Edwards ◽  
Stephen L Ogin ◽  
David A Jesson ◽  
Matthew Oldfield ◽  
Rebecca L Livesey ◽  
...  
Keyword(s):  
Fiber Composite ◽  
Plane Deformation ◽  
Ballistic Impact ◽  
Image Correlation ◽  
Composite Panel ◽  
Composite Panels ◽  
Micro Computed Tomography ◽  
Ballistic Performance ◽  
Low Level ◽  
Out Of Plane

Military personnel use protective armor systems that are frequently exposed to low-level damage, such as non-ballistic impact, wear-and-tear from everyday use, and damage during storage of equipment. The extent to which such low-level pre-damage could affect the performance of an armor system is unknown. In this work, low-level pre-damage has been introduced into a Kevlar/phenolic resin-starved composite panel using tensile loading. The tensile stress–strain behavior of this eight-layer material has been investigated and has been found to have two distinct regions; these have been understood in terms of the microstructure and damage within the composite panels investigated using micro-computed tomography and digital image correlation. Ballistic testing carried out on pristine (control) and pre-damaged panels did not indicate any difference in the V50 ballistic performance. However, an indication of a difference in response to ballistic impact was observed; the area of maximal local out-of-plane deformation for the pre-damaged panels was found to be twice that of the control panels, and the global out-of-plane deformation across the panel was also larger.

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