Compression tests on aluminum honeycomb and epoxy resin sandwich panels

2015 ◽  
Vol 4 (2) ◽  
pp. 157-163 ◽  
Author(s):  
Shuliang Cheng ◽  
Xuya Zhao ◽  
Bo Xiao ◽  
Yajun Xin
Keyword(s):  
Epoxy Resin ◽  
Sandwich Panels ◽  
Compression Tests ◽  
Aluminum Honeycomb

scholarly journals Ballistic Resistance of Honeycomb Sandwich Panels under In-Plane High-Velocity Impact

2013 ◽  
Vol 2013 ◽  
pp. 1-20 ◽  
Author(s):  
Chang Qi ◽  
Shu Yang ◽  
Dong Wang ◽  
Li-Jun Yang
Keyword(s):  
Structural Parameters ◽  
Sandwich Panels ◽  
Unit Cell ◽  
Dynamic Responses ◽  
Honeycomb Core ◽  
Ballistic Resistance ◽  
Honeycomb Sandwich ◽  
Aluminum Honeycomb ◽  
Parametric Studies ◽  
Nonmonotonic Effects

The dynamic responses of honeycomb sandwich panels (HSPs) subjected to in-plane projectile impact were studied by means of explicit nonlinear finite element simulations using LS-DYNA. The HSPs consisted of two identical aluminum alloy face-sheets and an aluminum honeycomb core featuring three types of unit cell configurations (regular, rectangular-shaped, and reentrant hexagons). The ballistic resistances of HSPs with the three core configurations were first analyzed. It was found that the HSP with the reentrant auxetic honeycomb core has the best ballistic resistance, due to the negative Poisson’s ratio effect of the core. Parametric studies were then carried out to clarify the influences of both macroscopic (face-sheet and core thicknesses, core relative density) and mesoscopic (unit cell angle and size) parameters on the ballistic responses of the auxetic HSPs. Numerical results show that the perforation resistant capabilities of the auxetic HSPs increase as the values of the macroscopic parameters increase. However, the mesoscopic parameters show nonmonotonic effects on the panels' ballistic capacities. The empirical equations for projectile residual velocities were formulated in terms of impact velocity and the structural parameters. It was also found that the blunter projectiles result in higher ballistic limits of the auxetic HSPs.

scholarly journals Fibers Networks as a New Type of Core Material. Processing and Mechanical Properties

2009 ◽  
Vol 1188 ◽  
Author(s):  
Laurent Mezeix ◽  
Christophe Bouvet ◽  
Serge Crézé ◽  
Dominique Poquillon
Keyword(s):  
Epoxy Resin ◽  
Carbon Fibers ◽  
Sandwich Panels ◽  
Open Architecture ◽  
Core Material ◽  
Cross Linking ◽  
Damping Capacity ◽  
The Core ◽  
Water Accumulation ◽  
Core Materials

AbstractMany different sandwich panels are used for aeronautical applications. Open and closed cell structured foam, balsa wood or honeycomb are often used as core materials. When the core material contains closed cells, water accumulation into the cell has to be taken into account. This phenomenon occurs when in service conditions lead to operate in humidity atmosphere. Then, water vapor from air naturally condenses on cold surfaces when the sandwich panel temperature decreases. This water accumulation might increase significantly the weight of the core material. Core with a ventilated structure helps to prevent this phenomenon. Periodic cellular metal (PCM) has been motivated by potential multifunctional applications that exploit their open architecture as well as their apparent superior strength and stiffness: pyramidal, lattice, Kagome truss or woven. One of the drawbacks of these materials is the expensive cost of the manufacturing. Recently, a novel type of sandwich has been developed with bonded metallic fibers as core material. This material presents attractive combination of properties like high specific stiffness, good damping capacity and energy absorption. Metal fibers bonded with a polymeric adhesive or fabricated in a mat-like form consolidated by solid state sintering. Entangled cross-linked carbon fibers have been also studied for using as core material by Laurent Mezeix. In the present study, ventilated core materials are elaborated from networks fibers. The simplicity of elaboration is one of the main advantages of this material. Multifunctional properties are given by mixing different sorts of fibers, by example adding fibers with good electrical conduction to give electrical conductivity properties. In this study network fibers as core material are elaborated using carbon fibers, glass fibers and stainless steel fibers. In aeronautical skins of sandwich panels used are often carbon/epoxy prepreg, so epoxy resin was used to cross-link fibers. The core thickness was chosen at 30 mm and fibers length was chosen at 40 mm. Entanglement, separation of filaments and cross-linking are obtained in a specific blower room. Fibers are introduced in the blower room, compressed air is applied and in same time epoxy resin is sprayed. Indeed one of the sandwich core material properties required is low density, so yarns size need to be decreased by separating filaments. Network fibers are introduced in a specific mould and then are compressed. The density obtained before epoxy spaying is 150 kg/m3. Finally samples are polymerized at 80°C for 2 hours in a furnace under laboratory air. Compressive behavior is study to determinate the influence of fibers natures and the effect of cross-linking. Reproducibility is also checked.

Performance assessment of rigid polyurethane foam core sandwich panels under blast loading

2019 ◽  
Vol 11 (1) ◽  
pp. 109-130 ◽  
Author(s):  
Hosein Andami ◽  
Hamid Toopchi-Nezhad
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Polyurethane Foam ◽  
Sandwich Panel ◽  
Sandwich Panels ◽  
Element Model ◽  
Polyurethane Foams ◽  
Compression Tests ◽  
Foam Layer ◽  
The Finite Element Model

The performance of rigid polyurethane foams, as an energy absorbent core of sandwich panels covered with two exterior steel sheets, was investigated numerically through finite element methods. After verifying the finite element model, numerical studies were conducted to investigate the role of thickness and density of the foam layer in the response behavior of sandwich panels under blast loads. A set of cylindrical polyurethane foam specimens were manufactured at five different nominal densities, 90, 140, 175, 220, and 250 kg/m3, and their stress–strain curves were evaluated using uniaxial compression tests. The test data were then employed to define characteristics of the polyurethane foams in the finite element model. Based on the results of finite element analysis runs, the optimum density of the foam layer was determined by assessing two response parameters including the peak pressure transmitted to the back face of the foam layer and the maximum deflection of sandwich panel. These response parameters were found to be affected differently by variations in the density of the foam layer within the panel. An increase in the thickness of the foam layer, to a certain extent, was found to be beneficial to the mitigation capability of sandwich panel.

Sandwich panels with layered graded aluminum honeycomb cores under blast loading

2017 ◽  
Vol 173 ◽  
pp. 242-254 ◽  
Author(s):  
Shiqiang Li ◽  
Xin Li ◽  
Zhihua Wang ◽  
Guiying Wu ◽  
Guoxing Lu ◽  
...  
Keyword(s):  
Sandwich Panels ◽  
Blast Loading ◽  
Aluminum Honeycomb ◽  
Honeycomb Cores

Dynamic behavior of aluminum honeycomb sandwich panels under air blast: Experiment and numerical analysis

2014 ◽  
Vol 108 ◽  
pp. 1001-1008 ◽  
Author(s):  
Xin Li ◽  
Peiwen Zhang ◽  
Zhihua Wang ◽  
Guiying Wu ◽  
Longmao Zhao
Keyword(s):  
Numerical Analysis ◽  
Dynamic Behavior ◽  
Sandwich Panels ◽  
Air Blast ◽  
Honeycomb Sandwich ◽  
Aluminum Honeycomb

scholarly journals Study on Bending Properties of Double Layer Aluminum Honeycomb Core Sandwich Panels

2006 ◽  
Vol 72 (724) ◽  
pp. 2050-2057 ◽  
Author(s):  
Yukiyoshi KOBAYASHI ◽  
Toshihisa OHTSUKA ◽  
Hiroshi TAMURA ◽  
Takehiro SATOH ◽  
Hiroyuki NAKAJIMA
Keyword(s):  
Double Layer ◽  
Sandwich Panels ◽  
Honeycomb Core ◽  
Bending Properties ◽  
Aluminum Honeycomb

scholarly journals Numerical Simulation and Experimental Research on Material Parameters Solution and Shape Control of Sandwich Panels with Aluminum Honeycomb

Open Physics ◽  
2019 ◽  
Vol 17 (1) ◽  
pp. 556-565
Author(s):  
Dongsheng Li ◽  
Mingming Wang ◽  
Xianbin Zhou
Keyword(s):  
Shape Control ◽  
Sandwich Panel ◽  
High Efficiency ◽  
Sandwich Panels ◽  
Simulation Method ◽  
Equivalent Material ◽  
Fe Model ◽  
Material Parameters ◽  
Surface Deviation ◽  
Aluminum Honeycomb

Abstract This paper aims to solve two problems of the sandwich panel with aluminum honeycomb: material parameters solution and shape control. The accurate material parameters of the sandwich panels are the basis of shape control. Therefore, a mixed numerical-experimental method is proposed to inversely solve equivalent material parameters of the sandwich panel using genetic algorithm (GA) in the first place. Then a high efficiency FE model based on equivalent material parameters is established to study shape control of the sandwich panels. For shape control, the key issue aims to search optimum position and adjustment volume of control points where actuators are installed. Toward the end, the FE simulation method is deployed to optimize actuator position and adjustment volume one by one. Finally, an active control platform based on multi-point adjustment is developed to verify the practicability of the approach proposed in this paper. Through the experiment of shape control, the root mean square (RMS) of surface deviation of sandwich panel is decreased from 62.7μm to 15.5μm. The results show that the shape control can significantly improve the surface accuracy of the sandwich panels, and the validity of equivalent material parameters is also proved from the side.

Fabrication, characterization and mechanical testing of carbon fiber sandwich composites with nanoparticle included polyurethane adhesives

2021 ◽  
pp. 002199832110588
Author(s):  
Mehmet Emin Çetin
Keyword(s):  
Carbon Fiber ◽  
Composite Structures ◽  
Bending Strength ◽  
Mechanical Performance ◽  
Synergistic Effects ◽  
Sandwich Panels ◽  
Sandwich Composite ◽  
Scanning Calorimetry ◽  
Aluminum Honeycomb ◽  
Out Of Autoclave

In honeycomb core and composite face sheet sandwich panels, it is essential to understand the bonding characteristics of adhesive in relevance with its properties to observe synergistic effects of reinforcing nanoparticles such as multi-walled carbon nanotubes (MWCNTs). This study investigates the effects of MWCNT inclusion on polyurethane (PU) adhesive, which directly affects sandwich structures' structural and mechanical performance. MWCNTs are added to PU adhesive up to 0.2%, and their RAMAN spectroscopic analysis, Fourier transform infrared spectroscopy (FT-IR), thermo-gravimetric analyses (TGA) and differential-scanning calorimetry analyses (DSC) are evaluated. Aluminum honeycomb carbon-fiber-reinforced composite (CFRC) sandwich panels are fabricated using an out-of-autoclave manufacturing process. Carbon-fiber prepreg is used for top/bottom face sheets. Mechanical strength of face/core bonding evaluated as a function of MWCNT addition and core cell sizes. Manufactured sandwich composite structures are investigated for flat-wise tensile strength and three-point bending strength. Results show that MWCNT reinforcement to PU adhesive and lower cell size increases bending and flat-wise tensile resistances.

Experimental and Optimization Study of Compression Behavior of Sandwich Panels with New Symmetric Lattice Cores

2021 ◽  
pp. 146442072110497
Author(s):  
Hossein Norouzi ◽  
Masoud Mahmoodi
Keyword(s):  
Sandwich Panel ◽  
Sandwich Panels ◽  
Weight Ratio ◽  
Quantitative Relationship ◽  
Compression Tests ◽  
Design Variables ◽  
Optimization Study ◽  
Predicted Values ◽  
Lattice Core ◽  
Initial Peak

The paper presents a novel core design for sandwich panels and conducts an experiment to determine whether the mechanical strength of symmetric aluminum lattice core sandwich panels can be improved. Both Design of Experiments (DOE) and Response Surface Methodology (Box-Behnken) were used to establish a quantitative relationship between the strength-to-weight ratio and the input parameters. The thickness of the sheet, the height of sandwich panels, and the width of the seat were all considered design variables to achieve the optimal state. The maximum Initial Peak Crushing Forces (IPCF) were then determined using quasi-static axial flatwise compression tests. This study found that the model's predicted values were consistent with the experimental results. As a result, the parameters were optimized using the Design-Expert software to maximize the initial peak force while minimizing the weight. The results were validated using the Genetic Algorithm, NSGA2, and LINGO. The results indicated that the height of the sandwich panel and the thickness of the sheet had the most significant impact on the maximum force and panel weight. To this end, it is concluded that introducing a novel core design for the sandwich panel, utilizing a suitable Snap-Fitting method for attaching lattice parts rather than using a paste, and finally optimizing the core were the primary reasons for achieving this level of strength.

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