DIFFERENT FAILURE MODES ASSESSMENT TO IMPROVE THE SANDWICH COMPOSITE PANEL STIFFNESS WITH HONEYCOMB CORE FOR MARINE STRUCTURES APPLICATION

2016 ◽  
Vol 78 (11) ◽  
Author(s):  
Mehdi Nakisa ◽  
Fatemeh Behrouzi ◽  
Ahmad Mobasher Amini
Keyword(s):  
Failure Modes ◽  
Compressive Load ◽  
Composite Panel ◽  
Face Sheet ◽  
Core Material ◽  
Sandwich Composite ◽  
Carbon Fiber Composites ◽  
Honeycomb Core ◽  
Marine Structures ◽  
The Core

This research paper focuses on the prediction of different failure modes to improve the sandwich composite panel with honeycomb core for application in marine structures. Marine, automotive and aerospace industries are continually trying to optimize material performance in terms of strength and weight. Success has been achieved through the growth of high performance materials, including fibrous composites such as ceramics, new alloys, and carbon fiber composites and through the use of structural concepts such as sandwich composite panel construction. Sandwich composite panel construction with honeycomb core consists of three components: two facing sheets, the core that fill the space between the facing sheet and the core-to-facing bonding adhesives. The facing sheets of a sandwich panel can be compared to the flanges of an I-beam element, as they carry the bending stresses to which the beam is subjected. With one facing sheet in compression, the other is in tension. Similarly the honeycomb core corresponds to the web of the I-beam that resists the shear loads and vertical compressive load to the face sheet. This paper presents a model for prediction of different failure mode of face sheet and core material. The obtained results of this model were compared with experimental results and presents that it is a simple and good model.  

scholarly journals Acoustic Panels Made of Paper Sludge and Clay Composites

2021 ◽  
Vol 13 (2) ◽  
pp. 637
Author(s):  
Tomas Astrauskas ◽  
Tomas Januševičius ◽  
Raimondas Grubliauskas
Keyword(s):  
Absorption Coefficient ◽  
Sound Absorption ◽  
Composite Panel ◽  
Sound Absorption Coefficient ◽  
Core Material ◽  
Paper Sludge ◽  
Frequency Range ◽  
Absorption Properties ◽  
Air Gaps ◽  
The Core

Studies on recycled materials emerged during recent years. This paper investigates samples’ sound absorption properties for panels fabricated of a mixture of paper sludge (PS) and clay mixture. PS was the core material. The sound absorption was measured. We also consider the influence of an air gap between panels and rigid backing. Different air gaps (50, 100, 150, 200 mm) simulate existing acoustic panel systems. Finally, the PS and clay composite panel sound absorption coefficients are compared to those for a typical commercial absorptive ceiling panel. The average sound absorption coefficient of PS-clay composite panels (αavg. in the frequency range from 250 to 1600 Hz) was up to 0.55. The resulting average sound absorption coefficient of panels made of recycled (but unfinished) materials is even somewhat higher than for the finished commercial (finished) acoustic panel (αavg. = 0.51).

Damage behavior of potting materials in sandwich composites with pinned joints

2015 ◽  
Vol 22 (5) ◽  
Author(s):  
Cesim Atas ◽  
Alper Basmaci
Keyword(s):  
Core Material ◽  
Sandwich Composite ◽  
Composite Panels ◽  
Sandwich Composites ◽  
Resin Infusion ◽  
Damage Behavior ◽  
Mechanical Joints ◽  
The Core ◽  
Bottom Face ◽  
Infusion Technique

AbstractThe damage behavior of the potting materials around a pinhole, being used in the mechanical joints of sandwich composites, is investigated experimentally. The sandwich composite panels used in the tests were manufactured by the vacuum-assisted resin infusion technique. Each of the top and bottom face sheets of the panels consisted of two woven E-glass/epoxy layers. As the core material, PVC foam (AIREX

Impact Analysis of Honeycomb Core Sandwich Panels

2020 ◽  
Author(s):  
Shah Alam ◽  
Damodar Khanal
Keyword(s):  
Sandwich Panels ◽  
Sheet Thickness ◽  
Composite Panel ◽  
Face Sheet ◽  
Impact Behavior ◽  
Front Face ◽  
Geometrical Parameters ◽  
Honeycomb Core ◽  
Back Face ◽  
The Impact

Abstract The goal of this paper is to analyze the impact behavior among geometrically different sandwich panels shown upon impact velocities. Initially, composite model with aluminum honeycomb core and Kevlar (K29) face sheets is developed in ABAQUS/Explicit and different impact velocities are applied. Keeping other parameters constant, model is simulated with T800S/epoxy face sheets. Residual velocities, energy absorption (%), and maximum deformation depth is calculated for sandwich panel for both models at five different velocities by executing finite element analysis. Once the better material is found for face sheets, process is extended by varying the ratio of front face sheet thickness to back face sheet thickness keeping other geometrical parameters constant to find the better geometry. Also, comparison of impact responses of sandwich composite panel on different ratio of front face sheet thickness to back face sheet thickness is done and validated with other results available in literature.

scholarly journals Moisture Absorption Effects on the Mechanical Properties of Sandwich Biocomposites with Cork Core and Flax/PLA Face Sheets

Molecules ◽  
2021 ◽  
Vol 26 (23) ◽  
pp. 7295
Author(s):  
Hom Nath Dhakal ◽  
Chulin Jiang ◽  
Moumita Sit ◽  
Zhongyi Zhang ◽  
Moussa Khalfallah ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Failure Modes ◽  
Moisture Absorption ◽  
Mechanical Performance ◽  
Core Sample ◽  
Environmental Benefits ◽  
Matrix Cracking ◽  
Core Material ◽  
Poly Lactic Acid ◽  
The Core

The aim of this study was to evaluate the moisture absorption behaviour and its influence on the mechanical properties of newly developed sandwich biocomposites with flax fibre-reinforced poly-lactic acid (PLA) face sheets and soft cork as the core material. Three different types of sandwich biocomposite laminates comprised of different layup configurations, namely, non-woven flax/PLA (Sample A), non-woven flax/PLA and cork as core (Sample B) and non-woven flax/paper backing/PLA, cork as core (Sample C), were fabricated. In order to evaluate the influence of moisture ingress on the mechanical properties, the biocomposites were immersed in seawater for a period of 1200 h. The biocomposites (both dry and water immersed) were then subjected to tensile, flexural and low-velocity falling weight impact tests. It was observed from the experimental results that the moisture uptake significantly influenced the mechanical properties of the biocomposites. The presence of the cork and paper in sample C made it more susceptible to water absorption, reaching a value of 34.33%. The presence of cork in the core also has a considerable effect on the mechanical, as well as energy dissipation, behaviours. The results of sample A exhibited improved mechanical performance in both dry and wet conditions compared to samples B and C. Sample A exhibits 32.6% more tensile strength and 81.4% more flexural strength in dry conditions than that in sample C. The scanning electron microscopy (SEM) and X-ray micro-CT images revealed that the failure modes observed are a combination of matrix cracking, core crushing and face core debonding. The results from this study suggest that flax/PLA sandwich biocomposites can be used in various lightweight applications with improved environmental benefits.

On the mechanisms of modal damping in FRP/honeycomb sandwich panels

2018 ◽  
Vol 25 (4) ◽  
pp. 649-660
Author(s):  
Aslan Abbasloo ◽  
Mohamad Reza Maheri
Keyword(s):  
Sandwich Panels ◽  
Shear Deformation Theory ◽  
Core Material ◽  
Honeycomb Core ◽  
The Core ◽  
Modal Damping ◽  
Reinforced Plastic ◽  
End Conditions ◽  
Modes Of Vibration ◽  
Bending Ratio

Abstract Sandwich panels made of fibre-reinforced plastic (FRP) skins and a honeycomb core can be effectively damped through the choice of the skin and especially of the core materials. Because the core is often highly damped, a lateral deflection that causes more shearing of the core than bending of the skin increases sandwich damping. Aside from the skin and the core material properties, the shearing/bending ratio depends on a number of other, often interacting, factors, including the sandwich planar as well as transverse dimensions, the particular modal pattern in which the panel vibrates and its relationship to the type of skin layup, as well as the panel end conditions. In the present work, using a simple, first-order shear deformation theory, damping results have been produced for simple modes of vibration of a sandwich panel comprising composite skins and a damped honeycomb core, demonstrating the mechanisms by which the above factors affect the FRP skin/honeycomb core sandwich damping.

The influence of different types of core materials on the impact behaviour of sandwich composites

2018 ◽  
pp. 78-83
Author(s):  
Cihan Kaboglu
Keyword(s):  
Sandwich Structures ◽  
Core Material ◽  
Sandwich Composite ◽  
Balsa Wood ◽  
Impact Behaviour ◽  
The Core ◽  
Glass Fibre Reinforced Polymer ◽  
Glass Fibre Reinforced ◽  
The Impact ◽  
Core Materials

Sandwich structures are popular in applications in which the weight of the component affects the efficiency, especially in the aviation and aerospace industries. This study aims to understand the impact behaviour of sandwich structures with different core materials. Sandwich structures are manufactured with glass fibre reinforced polymer skins and balsa wood, polyethylene terephthalate (PET) and polyvinyl chloride (PVC) core through resin infusion under flexible tools. Three different core materials were tested and compared using the damaged area of the back face of the sample. The effect of the core materials on the mechanical behaviour of the structures is crucial. The results showed that the microstructure of the core materials plays an important role, because althoughthe density of balsa wood is greater than the density of PET and PVC, the structures having PVC and PET as core materials undergo less damage than those having balsa wood as a core material. Keywords: Sandwich composite, impact behaviour, core materials.

Mechanical Reinforcement of Three-Dimensional Spacer Fabric Composites

2010 ◽  
Vol 654-656 ◽  
pp. 2604-2607 ◽  
Author(s):  
Shao Kai Wang ◽  
Min Li ◽  
Yi Zhuo Gu ◽  
Zuo Guang Zhang ◽  
Bo Ming Wu
Keyword(s):  
Failure Modes ◽  
Synergistic Effects ◽  
Three Dimensional ◽  
Compressive Load ◽  
Mechanical Reinforcement ◽  
The Core ◽  
Fabric Composite ◽  
Spacer Fabric ◽  
Fabric Composites ◽  
Foam Filling

Three-dimensional (3-D) spacer fabric composite is a novel lightweight sandwich structure, the reinforcement of which is integrally woven with two facesheets connected by continuous fibers (named piles) in the core. Usually the 3-D spacer fabric composite without extra reinforcement is called mono-spacer fabric composite, which provides outstanding facesheet / core debonding resistance. However, its mechanical properties cannot meet the demand of structure application because of the thin facesheet and low load-bearing capacity of high piles. Hence, two reinforcement methods were developed by laminating additional weaves at the facesheet and filling foam materials in the core to strengthen the facesheet and piles, respectively. This paper aims to investigate the influences of reinforcement methods on the mechanical behaviors and damage modes of 3-D spacer fabric composites under flatwise compressive, shear, edgewise compressive and three-point bending loads, by comparing with mono-spacer fabric composites. The results indicate that additional weaves reinforcement can enhance edgewise compressive and flexural properties effectively. Foam filling is one of the best options to improve the flatwise compressive and shear properties, and especially, there are synergistic effects between piles and foam under flatwise compressive load. Besides, the failure modes of reinforced and mono-spacer fabric composites are different.

scholarly journals PENGARUH TEBAL STYROFOAM CORE TERHADAP BERAT JENIS DAN KEKUATAN TEKAN KOMPOSIT SANDWICH MATRIKPOLYESTER DIPERKUAT SERAT SISAL DAN SERAT POHON PISANG

2012 ◽  
Vol 2 (1) ◽  
Author(s):  
S. Sinarep ◽  
Agus Dwi Catur
Keyword(s):  
Compressive Strength ◽  
Specific Gravity ◽  
Wood Products ◽  
Core Material ◽  
Sisal Fiber ◽  
Sandwich Composite ◽  
Composite Sandwich ◽  
The Core ◽  
Banana Tree ◽  
Core Thickness

Sandwich composite structure consisting of a core is flanked by two skin.  Therefore, the density of the composite sandwich are influenced by core composites material, the more light core the more lightweight composite produced. So also with the composite compressive strength is also very dependent on the core material. In this paper discussed the influence of core thickness on density and compressive strength of composite sandwich. Sisal fiber or  banana tree fibers that have been woven embedded in polyester composites to strengthen the skin. Composite core (Styrofoam) inserted between the two types of laminated composites to reduce weight and increase rigidity. The variation of the thickness of the core is applied in the manufacture of composites. Made of composite density was measured for specific gravity compared to wood or wood products on the market. Compressive strength of composite was characterized to determine the effect of core thickness on the compressive strength of composites.Research results show that the density of composite decreases with increasing thickness of  styrofoam core. Sandwich composite density is much smaller than the specific gravity of wood or wood products on the market.

scholarly journals Core failure in sandwich structures subjected to water slamming loads

2019 ◽  
Vol 21 (5) ◽  
pp. 1751-1772
Author(s):  
MA Battley ◽  
TD Allen
Keyword(s):  
Transverse Shear ◽  
High Speed ◽  
Failure Modes ◽  
Sandwich Panels ◽  
Core Material ◽  
Polymeric Foams ◽  
Failure Mechanics ◽  
The Core ◽  
High Elongation ◽  
Core Materials

Sandwich composite materials are widely used within the marine industry, particularly as hull panels. Water impact loads, known as slamming, can be very significant for these structures, particularly for high-speed craft. These loadings generate local regions of high transverse shear forces near panel boundaries, which can result in transverse shear failures of core materials. The transient nature of slamming loads can cause stress rates that are high enough to affect the strength of the core material, particularly for polymeric foams. Despite the significant body of work on the constitutive behaviour and failure mechanics of sandwich core materials, there is a lack of understanding of how core materials fail in transverse shear during slamming events. There is also only very limited knowledge of how the core shear strengths measured using standardised, often quasi-static material coupon testing relate to their behaviour in a panel-slamming situation. This paper contributes in two novel areas; controlled experimental characterisation of the failure mechanics of sandwich panels subjected to water slamming to understand and quantify the strength of different polymeric core materials, comparison of the failure modes and transverse shear strength of slam-loaded sandwich panels to predictions from material coupon properties. Core types include low, medium and high elongation polymeric foams. The results demonstrate that the more ductile foams perform better as panel structures under slamming relative to their quasi-static properties compared with the more brittle cores. Prediction of the strength of a panel is shown to be highly dependent on the load distribution and whether the static or dynamic core strength is considered. The results support empirical experience that ductile foams perform well under slamming loads, and that high-elongation materials can perform better in slamming situations than predicted by their quasi-static strengths.

scholarly journals An Investigation on Low Velocity Impact Response of Multilayer Sandwich Composite Structures

2013 ◽  
Vol 2013 ◽  
pp. 1-9 ◽  
Author(s):  
S. Jedari Salami ◽  
M. Sadighi ◽  
M. Shakeri ◽  
M. Moeinfar
Keyword(s):  
Composite Structures ◽  
Sandwich Panel ◽  
Testing Machine ◽  
Impact Response ◽  
Low Velocity Impact ◽  
Core Material ◽  
Sandwich Composite ◽  
Low Velocity ◽  
Velocity Impact ◽  
The Core

The effects of adding an extra layer within a sandwich panel and two different core types in top and bottom cores on low velocity impact loadings are studied experimentally in this paper. The panel includes polymer composite laminated sheets for faces and the internal laminated sheet called extra layer sheet, and two types of crushable foams are selected as the core material. Low velocity impact tests were carried out by drop hammer testing machine to the clamped multilayer sandwich panels with expanded polypropylene (EPP) and polyurethane rigid (PUR) in the top and bottom cores. Local displacement of the top core, contact force and deflection of the sandwich panel were obtained for different locations of the internal sheet; meanwhile the EPP and PUR were used in the top and bottom cores alternatively. It was found that the core material type has made significant role in improving the sandwich panel’s behavior compared with the effect of extra layer location.

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