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

Tension and compression of sandwich composites with weft-knit fabric cores

2020 ◽  
Vol 34 (07n09) ◽  
pp. 2040004
Author(s):  
Jieng-Chiang Chen ◽  
Yi-Fang Zhuang
Keyword(s):  
Compressive Force ◽  
Core Layer ◽  
Longitudinal Force ◽  
Test System ◽  
Core Material ◽  
Sandwich Composite ◽  
Sandwich Composites ◽  
Carbon Fabric ◽  
The Core ◽  
Tension And Compression

The manufacturing techniques of sandwich composites containing core layers of weft-knit glass fabric (WG) and weft-knit carbon fabric (WC) with carbon fabric skin layers are discussed herein. The core layers of the sandwich composites were fabricated with WG-reinforced epoxy (E) resin, WC-reinforced epoxy resin, and polyurethane foam (F). The core layer was then stacked with two pieces of carbon fabric on the top and bottom surfaces to fabricate the sandwich composites. Three sandwich composites [plain carbon fabric sandwich composite with a WG core layer (C/E/WG), plain carbon fabric sandwich composite with a WC core layer (C/E/WC), and plain carbon fabric sandwich composite with an F core layer (C/E/F)] were developed in this study. A two-step manufacturing procedure was developed to achieve sufficient adhesiveness between the skin and core layers. The tensile, flatwise compressive, and longitudinal compressive properties of these sandwich composites were measured according to referred ASTM standards on a materials test system (MTS 810). Experimental results revealed that the WC core materials displayed excellent resistance to a flatwise compressive force and the foam core material show weak resistance. Under longitudinal compression, the skin and core layer of the C/E/F specimen separated, indicating that the C/E/F specimen could not withstand longitudinal force. Moreover, the C/E/WG and C/E/WC specimens both bend at the end of the same test.

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.

Researches Concerning Structural and Mechanical Behavior of Sandwich Composite Polymeric Products

2012 ◽  
Vol 498 ◽  
pp. 151-160 ◽  
Author(s):  
Constantin Gheorghe OPRAN ◽  
Cătălina Bivolaru ◽  
Diana Murar
Keyword(s):  
Mechanical Behavior ◽  
Structural Behavior ◽  
Sandwich Composite ◽  
Flexural Stiffness ◽  
Constant Force ◽  
Sandwich Composites ◽  
Fiber Glass ◽  
The Core ◽  
Weight Saving ◽  
Specific Factors

The sandwich composite polymeric products have a wide utilization in various fileds like aircraft and automotive construction, load bearing structures, sports equipment, more specifically, wherever weight-saving is required. Sandwich composites polymeric products represent excellent examples of the potential offered by composite materials. The combination of two composite faces and a lightweight polystyrene core allows obtaining a high flexural stiffness with a weak mass. This paper deals with the analysis of the structural and mechanical behavior properties of the core, adhesive and faces, for sandwich composite polymeric products. There are also presented the investigation results on how different specific factors like: mechanical and structural behavior, interface between the faces and core, constant force resistance in time, the reinforcing elements (fiber glass), the polyester core do influence the machinability of sandwich composites polymeric products..

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.

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 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.

Bending and impacting of sandwich composites with a corrugated paper core layer

2018 ◽  
Vol 32 (19) ◽  
pp. 1840057 ◽  
Author(s):  
Jieng-Chiang Chen
Keyword(s):  
Core Layer ◽  
Test System ◽  
Absorption Capacity ◽  
Sandwich Composite ◽  
Sandwich Composites ◽  
Hot Press ◽  
Jute Fabric ◽  
The Core ◽  
The Impact ◽  
Corrugated Paper

The bending and impacting characteristics of sandwich composites containing corrugated paper (CP) as a core layer are discussed herein. The core layer of the sandwich composite was fabricated with CP-reinforced polylactic acid (PLA) resin. The core layer was then stacked with jute fabric and PLA films on the top and bottom surfaces to fabricate the sandwich composites. Two composites [CP-reinforced PLA composite (CP/PLA composite)] and jute fabric/PLA sandwich composite with CP as a core layer [J/PLA/CP composite] were developed in this study. To manufacture the CP/PLA composite core layer, a dipping bath was used for impregnating the paper with a molten PLA solution. The resin film method combined with a hot press was used to produce the jute fabric/PLA/CP sandwich composites. A material test system (MTS810) was used to study the bending properties of the composites. Further, an IZOD impacting instrument was used to examine the impacting characteristics of the composites. Both the CP/PLA and jute fabric/PLA/CP sandwich composites increase the energy absorption capacity in the impact test.

Dynamic characteristics of sandwich composite with debonding

2018 ◽  
Vol 32 (9) ◽  
pp. 1204-1223
Author(s):  
M Idriss ◽  
A El Mahi
Keyword(s):  
Finite Element ◽  
Dynamic Characteristics ◽  
Flexural Vibration ◽  
Experimental Tests ◽  
Core Material ◽  
Sandwich Composite ◽  
Dissipated Energy ◽  
Stress And Strain ◽  
Sandwich Composites ◽  
Modal Strain Energy

The article presents the results of experimental and finite element analyses of the flexural vibration behavior sandwich composite with different debonding ratios. Sandwich composite consists of two thin skins composed of E-glass fiber and epoxy resin bonded to lightweight and weaker core material of PVC foams. Experimental tests using the impulse technique were performed on the sandwich constituents and sandwich composites with different debonding lengths. The modal dynamic characteristics of sandwich composite were measured and discussed for each debonding ratio. A finite element modeling was used to determine the natural frequencies, modal shapes, and stress and strain fields for each element of sandwich composites for each debonding ratio. The modal strain energy approach was used to determine the contribution of energies dissipated of the core and the skins in the total dissipated energy and the global damping of the different sandwich composites. The results obtained by this approach are compared with those obtained experimentally.

Silicone/Carbon Nanotube Sheet Biofidelic Piezoresistive Sandwich Composites

2019 ◽  
Vol 142 (1) ◽  
Author(s):  
Nengda Jiang ◽  
Sirish Namilae ◽  
Vinu Unnikrishnan
Keyword(s):  
Mechanical Properties ◽  
Biomedical Applications ◽  
Polymeric Materials ◽  
Analytical Models ◽  
Sandwich Composite ◽  
Sandwich Composites ◽  
Human Brain Tissue ◽  
Electrically Conductive ◽  
The Core ◽  
Electromechanical Performance

Abstract Silicone-based biofidelic surrogates are used in many biomedical applications. Apart from mimicking the mechanical behavior of bodily tissues, there is an increasing requirement for these materials to be electrically conductive and piezoresistive to facilitate direct instrumentation. Carbon nanotubes (CNTs) have been extensively investigated as fillers to impart electrical conductivity and piezoresistivity to polymeric materials including silicone. In this paper, we fabricate, test, and characterize a two-part silicone/CNT sheet sandwich composites that exhibit conductivity, piezoresistivity, and biofidelic with mechanical properties corresponding to that of the white matter of human brain tissue. The electromechanical performance of the sandwich composite improves in subsequent loading after the core fracture during initial loading. Analytical models developed for discontinuous core sandwich structures are used to analyze and explain the experimental results. The results indicate the potential for using this discontinuous core biofidelic-piezoresistive sandwich nanocomposite for biomedical applications without deploying external deformation sensors.

Tensile and compressive performances of foam core sandwich composites with various core modifications

2016 ◽  
Vol 19 (1) ◽  
pp. 49-65 ◽  
Author(s):  
Huseyin E Yalkin ◽  
Bulent M Icten ◽  
Tuba Alpyildiz
Keyword(s):  
Sandwich Composite ◽  
Foam Core ◽  
Sandwich Composites ◽  
Time Consumption ◽  
The Core ◽  
Out Of Plane

The objective of this study is to enhance the out-of-plane tensile and compressive performances of foam core sandwich composite via structural core modifications considering the ease of application and time consumption. The performances of single core perforated, single core stitched, divided core perforated, and divided core stitched sandwich composites are compared with each other and reference plain foam core sandwich composites. Results indicate that “perforated and stitched core” sandwich composites have superior strength, and in terms of performance modification, dividing the core is found very efficient for plain (non-perforated and non-stitched) core sandwich composites.

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