scholarly journals DETERMINATION OF MECHANICAL PROPERTIES OF COMPOSITE SANDWICH PANEL WITH ALUMINIUM HONEYCOMB CORE

2021 ◽  
Vol 2021 (6) ◽  
pp. 5353-5359
Author(s):  
MICHAL SKOVAJSA ◽  
◽  
FRANTISEK SEDLACEK ◽  
MARTIN MRAZEK ◽  
◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Numerical Simulation ◽  
Sandwich Panel ◽  
Analytical Calculation ◽  
Sandwich Panels ◽  
Honeycomb Core ◽  
Composite Sandwich Panels ◽  
Composite Sandwich ◽  
Three Point Bend Test ◽  
Honeycomb Cores

This paper deal with comparison of mechanical properties of composite sandwich panel with aluminium honeycomb core which is determined by experimental measurement, analytic calculation and numerical simulation. The goal was to compared four composite sandwich panels. The composite sandwich panels were made of two different aluminium honeycomb cores with density 32 and 72 kg.m-3 and two different layup of skin with 4 and 5 layers. The comparison was performed on a three-point bend test with support span 400 mm. This paper confirms the possibility of a very precise design of a composite sandwich panel with an aluminium honeycomb core using analytical calculation and numerical simulation.

scholarly journals High Temperature Mechanical Properties of a Vented Ti-6Al-4V Honeycomb Sandwich Panel

Materials ◽  
2020 ◽  
Vol 13 (13) ◽  
pp. 3008
Author(s):  
Lei Shang ◽  
Ye Wu ◽  
Yuchao Fang ◽  
Yao Li
Keyword(s):  
Mechanical Properties ◽  
High Temperature ◽  
Cell Walls ◽  
Sandwich Panel ◽  
Sandwich Panels ◽  
Honeycomb Core ◽  
Compression Performance ◽  
High Temperature Mechanical Properties ◽  
Honeycomb Sandwich ◽  
The Face

For aerospace applications, honeycomb sandwich panels may have small perforations on the cell walls of the honeycomb core to equilibrate the internal core pressure with external gas pressure, which prevent face-sheet/core debonding due to pressure build-up at high temperature. We propose a new form of perforation on the cell walls of honeycomb sandwich panels to reduce the influence of the perforations on the cell walls on the mechanical properties. In this paper, the high temperature mechanical properties of a new vented Ti-6Al-4V honeycomb sandwich panel were investigated. A vented Ti-6AL-4V honeycomb sandwich panel with 35Ti-35Zr-15Cu-15Ni as the filler alloy was manufactured by high-temperature brazing. The element distribution of the brazed joints was examined by means of SEM (scanning electron microscopy) and EDS (energy-dispersive spectroscopy) analyses. Compared to the interaction between the face-sheets and the brazing filler, the diffusion and reaction between the honeycomb core and the brazing filler were stronger. The flatwise compression and flexural mechanical properties of the vented honeycomb sandwich panels were investigated at 20, 160, 300, and 440 °C, respectively. The flatwise compression strength, elastic modulus, and the flexural strength of the vented honeycomb sandwich panels decreased with the increase of temperature. Moreover, the flexural strength of the L-direction sandwich panels was larger than that of the W-direction sandwich panels at the same temperature. More importantly, the vented honeycomb sandwich panels exhibited good compression performance similar to the unvented honeycomb sandwich panels, and the open holes on the cell walls have no negative effect on the compression performance of the honeycomb sandwich panels in these conditions. The damage morphology observed by SEM revealed that the face-sheets and the brazing zone show ductile and brittle fracture behaviors, respectively.

scholarly journals Hygrothermal Deformation of Composite Sandwich Panels

2000 ◽  
Vol 9 (1) ◽  
pp. 096369350000900 ◽  
Author(s):  
Ernest G. Wolff ◽  
Hong Chen ◽  
Darrell W. Oakes
Keyword(s):  
Composite Laminates ◽  
Sandwich Panels ◽  
Adhesive Properties ◽  
Modified Model ◽  
Moisture Expansion ◽  
Composite Sandwich Panels ◽  
Composite Sandwich ◽  
Laminate Theory ◽  
Nomex Honeycomb ◽  
Honeycomb Cores

Coefficients of thermal and moisture expansion (CTE and CME) can be predicted for many composite laminates and sandwich panels. Core and adhesive properties, such as geometry and stiffness are important variables. Laminate theory is augmented with a modified model for anisotropic core properties to predict the CTE and CME of sandwich panels. Procedures to measure both CTE and CME are described. Since these are thermodynamic properties, methods to obtain equilibrium moisture strains are needed. Results are given for CFRP facesheets with Al and NOMEX honeycomb cores, and for woven Kevlar facesheets with Al cores. Agreement with predictions is good and depends highly on knowledge of properties of all constituents.

scholarly journals Multi-Criteria Optimization of Energy-Efficient Cementitious Sandwich Panels Building Systems Using Genetic Algorithm

Energies ◽  
2021 ◽  
Vol 14 (18) ◽  
pp. 6001
Author(s):  
Ehsan Mirnateghi ◽  
Ayman S. Mosallam
Keyword(s):  
Genetic Algorithm ◽  
Optimum Design ◽  
Energy Efficient ◽  
Sandwich Panel ◽  
Sandwich Panels ◽  
Optimization Techniques ◽  
Pareto Optimal ◽  
Cementitious Composite ◽  
Composite Sandwich Panels ◽  
Composite Sandwich

This paper presents results of a study that focuses on developing a genetic algorithm (GA) for multi-criteria optimization of orthotropic, energy-efficient cementitious composite sandwich panels (CSP). The current design concept of all commercially produced CSP systems is based on the assumption that such panels are treated as doubly reinforced sections without the consideration of the three-dimensional truss contribution of the orthotropic panel system. This leads to uneconomical design and underestimating both the strength and stiffness of such system. In this study, two of the most common types of commercially produced sandwich were evaluated both numerically and experimentally and results were used as basis for developing a genetic algorithm optimization process using numerical modeling simulations. In order to develop a sandwich panel with high structural performance, design optimization techniques are needed to achieve higher composite action, while maintaining the favorable features of such panels such as lightweight and high thermal insulation. The study involves both linear and nonlinear finite element analyses and parametric optimization. The verification and calibration of the numerical models is based on full-scale experimental results that were performed on two types of commercially produced sandwich panels under different loading scenarios. The genetic algorithm technique is used for optimization to identify an optimum design of the cementitious composite sandwich panels. The GA technique combines Darwin’s principle of survival of fittest and a structured information exchange using randomized crossover operators to evolve an optimum design for the cementitious sandwich panel. Parameters evaluated in the study include: (i) shear connectors’ geometry, its volume fraction and distribution; (ii) exterior cementitious face sheets thickness and (iii) size and geometry steel wires reinforcements. The proposed optimization method succeeded in reducing cost of materials of CSP by about 48% using genetic algorithm methodology. In addition, an optimized design for CSP is proposed that resulted in increasing the panel’s thermal resistance by 40% as compared to existing panels, while meeting ACI Code structural design criteria. Pareto-optimal front and Pareto-optimal solutions have been identified. Correlation between the design variables is also verified and design recommendation are proposed.

Experimental-Theoretical Research of Mechanical Properties of Perforated Composite Sandwich Panels

2015 ◽  
Vol 243 ◽  
pp. 1-10 ◽  
Author(s):  
A.N. Anoshkin ◽  
V.Yu. Zuiko ◽  
A.V. Tchugaynova ◽  
E.N. Shustova
Keyword(s):  
Mechanical Properties ◽  
Composite Materials ◽  
Theoretical Analysis ◽  
Tensile Testing ◽  
Sandwich Panels ◽  
Theoretical Research ◽  
Composite Sandwich Panels ◽  
Composite Sandwich ◽  
Fibrous Polymer ◽  
Fibrous Polymer Composite

This work is devoted to experimental-theoretical analysis of mechanical properties of sandwich panels made of fibrous polymer composite materials. The structures with tubular core were considered. Numerical simulations of the mechanical behaviour and tensile testing of full-scale samples of sandwich panels were done. The analysis of influence of perforation on mechanical properties of fiberglass laminates and sandwich panels was alsoperformed.

Evaluation of skin-core adhesion bond of out-of-autoclave honeycomb sandwich structures

2012 ◽  
Vol 31 (5) ◽  
pp. 331-339 ◽  
Author(s):  
R.R. Butukuri ◽  
V.P. Bheemreddy ◽  
K. Chandrashekhara ◽  
T.R. Berkel ◽  
K. Rupel
Keyword(s):  
Cell Size ◽  
Sandwich Structures ◽  
Sandwich Panels ◽  
Core Material ◽  
Honeycomb Core ◽  
Composite Sandwich Panels ◽  
Composite Sandwich ◽  
Film Adhesive ◽  
Adhesive Thickness ◽  
Out Of Autoclave

Composite sandwich structures offer several advantages over conventional structural materials such as lightweight, high bending and torsional stiffness, superior thermal insulation and excellent acoustic damping. One failure mechanism in a composite sandwich structure is the debonding of the composite facesheets from the core structure. A well-formed adhesive fillet at the interface of the honeycomb core cell walls and the laminate is a significant factor in preventing bond failure. In the present work, honeycomb composite sandwich panels are manufactured using a low-cost vacuum-bag-pressure-only out-of-autoclave manufacturing process. CYCOM®5320 out-of autoclave prepreg is used for the facesheet laminates and FM® 300-2U film adhesive is used for the facesheet-to-core bond. The manufactured composite sandwich panels are of aerospace quality with a facesheet laminate void content of around 1%. In this study, adhesive fillet formation and adhesive mechanical strength are evaluated as a function of several different sandwich construction design variables. Both aluminum and aramid Nomex® honeycomb core materials are considered to study the effect of core cell size and core material. The effect of film adhesive thickness is studied. A process for reticulation of the adhesive is applied and studied. A quantitative investigation of the adhesive fillet geometry is carried out for all the panels. Manufactured panels are evaluated for flatwise tensile strength in accordance with test method ASTM C297. Optimized combinations of core material, core density, cell size and adhesive thickness are identified. Results show that the reticulation process improves fillet formation and increases flatwise tensile properties.

Penetration and Perforation of Composite Sandwich Panels by Hemispherical and Conical Projectiles

1998 ◽  
Vol 120 (2) ◽  
pp. 186-194 ◽  
Author(s):  
T. Y. Reddy ◽  
H. M. Wen ◽  
S. R. Reid ◽  
P. D. Soden
Keyword(s):  
Static Loading ◽  
Sandwich Panel ◽  
Sandwich Panels ◽  
Diameter Ratio ◽  
Empirical Formulas ◽  
Composite Sandwich Panels ◽  
Composite Sandwich ◽  
First Approximation ◽  
Panel Thickness

The results of penetration and perforation tests carried out on composite sandwich panels with GRP skins and PVC foam cores using hemispherical-ended and conical-nosed indenters/projectiles under quasi-static, drop-weight, and ballistic impact conditions, with impact velocities up to 305 m/s, are described. Load-displacement characteristics under quasi-static loading are presented and the ballistic limits as well as perforation energies are determined. A classification of the sandwich panel responses based on the panel thickness-to-projectile diameter ratio is deduced. General empirical formulas that predict the dynamic perforation energies for FRP laminates and composite sandwich panels loaded by hemispherical-ended projectiles are derived. The empirical equations correlate well with available experimental data. It is shown that, to a first approximation, the formulas obtained for hemispherical-ended projectiles are also applicable to conical-nosed projectiles.

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