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.

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

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.

Preparation and Properties of a Novel Water Soluble Core Material for the Resin Transfer Molding Process

2011 ◽  
Vol 306-307 ◽  
pp. 844-847
Author(s):  
Quan Zhou Li ◽  
Xiao Qing Wu
Keyword(s):  
Compressive Strength ◽  
Resin Transfer Molding ◽  
Water Soluble ◽  
Core Material ◽  
Molding Process ◽  
Transfer Molding ◽  
The Core ◽  
Rtm Process ◽  
Binder Solution ◽  
Core Materials

A novel water soluble core material composed of alumina, quartz sand, kaolin, gypsum powder and the solution of binders was prepared. The influence of different mass concentration of Polyethylene Glycol (PEG) binder solution and sodium silicate compounded (SS) binders solution on water soluble performance and compressive strength of the core materials was investigated, respectively. The results show that the compressive strength and solubility rate of the core materials, with the concentration of 30% of SS binders solution, are 1.023MPa and 0.24g/s respectively, which is satisfied for the requirements of Resin Transfer Molding (RTM) process completely.

Three-Point Bending Shear Stress of Wooden Sandwich Composite

2016 ◽  
Vol 852 ◽  
pp. 1337-1341
Author(s):  
Xin Feng Wu ◽  
Jian Ying Xu ◽  
Jing Xin Hao ◽  
Rui Liao ◽  
Zhu Zhong
Keyword(s):  
Shear Stress ◽  
Shear Force ◽  
Sandwich Beam ◽  
Single Layer ◽  
Skin Layer ◽  
Sandwich Composite ◽  
Three Point Bending ◽  
The Core ◽  
Sandwich Construction ◽  
Core Thickness

The effect of construction parameters and material type on bending shear stress and shear force was analyzed systematically. It is shown that maximum bending shear stress of sandwich construction is smaller than homogeneous single layer beam with same cross section if the skin has higher modulus than the core. Besides the effect of core or skin layer to shear force is almost identical for sandwich composite composed by different materials with same construction parameter. In addition, the shear force can be taken almost by the core of sandwich beam only if the ratio of core thickness to the whole is more than. Otherwise the resistance to shear force of skin layer should be considered to calculate the shear deformation. The results can provide basic theory for design optimization of sandwich construction.

Load-Carrying Characteristics of Foam Core and Joint Geometry in Sandwich Structures

2020 ◽  
Author(s):  
Jonas W. Ringsberg
Keyword(s):  
Structural Integrity ◽  
Side Wall ◽  
Core Material ◽  
Fe Model ◽  
Foam Core ◽  
Stress Concentrations ◽  
Production Time ◽  
Composite Sandwich ◽  
The Core ◽  
Load Carrying

Abstract Composite sandwich ships have laminated joints that contribute to a significant part of the ship’s weight. Their construction requires an extensive number of man-hours. There is great potential for weight and production-time-reduction through alternative joint designs. According to class rules, one is not allowed to benefit from the load-carrying capability of the core, i.e. the strength characteristics of the core shall be disregarded and geometry at the joint location is disregarded as well. The objective of the current investigation was to investigate the possibility of constructing a joint where the load-carrying capability of the foam core is accounted for, leading to a reduction in weight and production time. One specific joint in a 23 m composite sandwich catamaran was selected for study — a side wall-wet deck T-joint. This joint is considered to be crucial for the structural integrity of the current vessel. A global finite element (FE) model of the catamaran was designed and analysed in ANSYS. The loads and boundary conditions were applied to the global model according to DNV GL’s HSLC rules. Two local FE models of the joints (2D and 3D) were utilized for a parametric analysis with respect to structure response (stress concentrations and compliance with failure and fracture criteria). Finally, the results and conclusions from the study show the possibilities and advantages of incorporating the foam core material as a load-carrying member in joint design without compromising safety.

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 Nonlinear Stress and Deformation Behaviour of Composite Sandwich Beams

2008 ◽  
Vol 13-14 ◽  
pp. 91-98 ◽  
Author(s):  
E.E. Gdoutos ◽  
I.M. Daniel
Keyword(s):  
Experimental Results ◽  
Core Material ◽  
Sandwich Beams ◽  
Stress Strain ◽  
Normal Stress Distribution ◽  
Nonlinear Load ◽  
Composite Sandwich ◽  
The Core ◽  
Nonlinear Stress ◽  
Load Displacement

The nonlinear load-displacement and normal stress distribution in composite sandwich beams made of unidirectional carbon/epoxy facings and PVC foam cores under bending was studied. The carbon/epoxy after an initial linear response exhibits a stiffening nonlinearity in tension and a softening nonlinearity in compression with the longitudinal strength in tension higher than that in compression. The foam core also presents a nonlinear stress-strain response. It was obtained that the load-displacement behaviour of the beam, after an initial linear part, is not linear. This behavior was modeled by an incremental strength of materials nonlinear analysis. The theoretical predictions were in good agreement with the experimental results. Furthermore, it was obtained that the neutral axis of sandwich beams under bending does not pass through the centroid of the cross section, but is displaced toward the tensile side of the beam. Experimental results by moiré measurements of the in-plane horizontal displacements of the core material corroborated the analytical predictions. These findings imply higher compressive and smaller tensile stresses in the core, than those predicted for facings with identical stress-strain behaviour in tension and compression, and should be taking into consideration in the failure analysis of sandwich beams.

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.

Dynamic stability of the double-bonded annular nanocomposite sandwich microplate on viscoelastic foundation

2021 ◽  
pp. 109963622110204
Author(s):  
Mohsen Emdadi ◽  
Mehdi Mohammadimehr
Keyword(s):  
Mechanical Properties ◽  
Dynamic Stability ◽  
Dynamic Instability ◽  
Couple Stress Theory ◽  
Shear Deformation Theory ◽  
Unit Cell ◽  
Core Material ◽  
Viscoelastic Foundation ◽  
The Core ◽  
Core Thickness

In this research, the dynamic stability of the double-bonded annular sandwich microplate is investigated. Face sheets are made from composite materials reinforced by carbon nanotubes in which mechanical properties are obtained by the extended rule of the mixture. Also, the core layer is made from a honeycomb aluminum which is defined by the geometric parameters of the unit cell and mechanical properties of the virgin core material. The equations of motion are derived from Hamilton’s principle and solved by the differential quadrature method (DQM) based on higher order shear deformation theory (HSDT) and modified couple stress theory (MCST). The results are compared with the obtained results by the other literature to examine the accuracy of the present formulation. The dynamic stability of the double-bonded annular sandwich microplate with hexagonal honeycomb core including variations of core thickness, inclined angle, and aspect ratio of the unit cell are discussed. Also, the effects of motion direction of the structure, viscoelastic foundation, material length scale parameter, volume fractions of CNTs in face sheets, and the core thickness to total thickness ratio on dynamic instability region are presented.

A Study of Hybrid Composite Sandwich Beam

2019 ◽  
Author(s):  
Shah Alam ◽  
Guoqiang Li
Keyword(s):  
Finite Element ◽  
Finite Element Modeling ◽  
Experimental Results ◽  
Core Material ◽  
Sandwich Beams ◽  
Premature Failure ◽  
Element Modeling ◽  
Composite Sandwich ◽  
The Core ◽  
Linear Variable Displacement Transducer

Abstract This study presents the testing and numerical modeling results of composite sandwich beams. The sandwich beams are constructed from balsa wood in the core and high strength steel wire and E-glass fiber reinforced polymer composite in the facings. The testing of these beams is performed using a monotonic static four-point loading to failure in accordance with ASTM C393-00. Local strain distribution in the mid-span of the beams is obtained using strain gauges. Mid-span deflections of the beams are real-time measured using linear variable displacement transducer (LVDT). From the experimental results, flexural properties of the beams are calculated, including bending stiffness, bending strength, core shear strength, and facing modulus, core modulus, etc. The experimental results have shown that the beams have all failed in the compression zone by local buckling of the top face and shear of the core. The bottom skin does not exhibit any type of premature failure or distress. No bond failure of the composite in the tension zone is observed in any of the tested beams. Finite element modeling of the beam has been conducted using ANSYS. The mechanical properties of the skin and core material used in finite element modeling have been determined by testing of coupons. The predicted results are compared to experimental results, with a reasonable agreement.

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