bluuebunny/crossref_metadata_2025 huggingface dataset:
Delamination Resistance of Fibre Reinforced Polymer (FRP) Plate Subjected to Out-of-Plane Loading
Authors: Kuboki T. , Jar P.-Y. B. , Cheng J. J. R.
Published: January 2019

Delamination resistance of fibre-reinforced polymer (FRP) was characterized directly from plates that were subjected to out-of-plane loading. Plate specimens used in the study were designed to be mainly unidirectional (0°), with a single layer containing fibre in the orthogonal direction (90°) inserted at the mid-thickness. The test set-up followed the description given in ASTM D3763-02, but using indenter of large radius to minimize the indentation damage. The study found that the out-of-plane loading on the top surface generated firstly a flexural splitting crack in the 0° direction from the bottom half of the plate. The splitting crack facilitated the delamination growth, resulting in a peanut-shaped area in the interlaminar region underneath the 90° layer. The delamination resistance was characterized using the rate of energy loss per unit area of delamination growth, of which the value was found to be consistent with that determined previously, using flexural tests on beam-type specimens.
Tensile Behaviour of SiC Coated Carbon/Carbon Composites after Exposure to a CH4 Combustion Gas
Authors: Liu Chidong , Cheng Laifei , Mei Hui , Luan Xingang , Huang Hui
Published: January 2019

Tensile behaviour and microstructure of a SiC coated C/C composite were investigated after exposure to a CH4 combustion gas with flame temperatures of 1300 °C and 1800 °C. The tensile strength of the composite was respectively reduced to 61.9% and 77.7% of their original values. Superficial oxidation of the C/C substrate was responsible for strength reduction. Multi-tube-walled structure of the C/C substrate was observed after oxidation, which was caused by the difference in reactivity between the carbon fibre and the matrix. Silica spheres were observed to adhere to the C/C substrate beneath the coating, which was caused by active oxidation of SiC.
Nano-Fibre Critical Length Depends on Shape
Authors: Goh K. L. , Huq A. M. A. , Aspden R. M. , Hukins D.W.L.
Published: January 2019

Nano-fibres in composite materials may not be cylindrical. A theoretical analysis shows that non-cylindrical nano-fibres have longer critical lengths leading to composites with different mechanical properties requiring a lower volume of reinforcing material.
Innovative Process for Manufacturing Laminates with Recycled Thermoplastic Reinforced by Natural Fibres
Authors: Durante M. , Visconti I. Crivelli
Published: January 2019

For the processing of thermoplastics reinforced with natural fibres a new method based on the vacuum bag has been employed. Agave fibres reinforcing polyethylene (PE) laminates have been manufactured adopting low cost technology and recycled materials (matrix and fibres). In particular starting from recycled PE shoppers and low cost fibres, laminates have been manufactured by vacuum bag moulding at relatively low values of temperature. This technology consents to manufacture large panels adopting very simple moulds. In order to evaluate the manufacturing process, the properties of composite materials, carried out by static and dynamic mechanical analysis (DMA), have been compared with the single matrix (PE) properties.
Metal Fibre Reinforced Composite – Potentialities and Tasks
Authors: Schmeer S. , Steeg M. , Maier M. , Mitschang P.
Published: January 2019

Steel fibres and Twintex® materials were prepared by compaction with a continuous compression molding press, equipped with temperature and pressure controlled plates. The material itself was observed by SEM analysis and mechanical properties were examined by different material tests. In spite of a non perfect interface and bonding the mechanical properties such as stiffness and strength were increased by adding steel fibres to Twintex® material. Even the specific values of stiffness and absorbed energy could be enhanced considerably.
An Experimental Investigation on the Impact Behaviour of Glass/Epoxy and Hybrid Composite Plates
Authors: Sayer Metin , Bektaş Numan B. , Sayman Onur , Topçu Muzaffer
Published: January 2019

In this study, the impact behaviours of glass/epoxy and hybrid (glass-carbon/epoxy) composite plates have been investigated experimentally. The increasing impact energy was performed on composite plates until complete perforation of samples. An energy profiling diagram, showing the relationship between impact energy and absorbed energy, was used together with load-deflection curves to determine the penetration and perforation thresholds of composite plates. The failure processes of damaged specimens for different impact energies were evaluated by comparing load-deflection curves and images of damaged samples taken from impacted sides and non-impacted sides. Cross-sections of damaged specimens for both plates were also inspected visually and discussed to assess the extent of damage, such as fibre fracture in layers, expansion of delaminations between adjacent layers. The perforation threshold of hybrid composite impacted from surface with carbon fibres was found approximately 30% and 15% higher than those of surface with glass fibres of hybrid plates and glass/epoxy plates, respectively.
Wear Characterisitcs of Nano-Particle Filled GFRP Composites
Authors: Srinivasan V. , Karthikeyan R. , Raffi N.Mohamad , Ganesan G.
Published: January 2019

In the recent years, the growth of glass fibre reinforced plastic (GFRP) is significantly higher than that of steel. In this study, the GFRP filled with 1 & 2% volume fraction of nano Alumina (Al2O3) particles were tested for their tribological behaviour. The wear maps were utilized to study the influence of control parameters like sliding velocity and normal force over the responses like coefficient of friction, contact temperature and wear rate. The micrographs of the worn out specimen showed the dominance of a particular wear mechanism in each sliding conditions.
Evaluation of the Fibre-Matrix Debond Strength of a Ti-22Al-23Nb (AT.%)/Trimarc Metal Matrix Composite
Authors: LeBoeuf J.L. , Boehlert C.J.
Published: January 2019

A methodology involving experimental testing using a cruciform specimen geometry has been developed which assists fibre/matrix debond strength calculations for continuously reinforced metal matrix composites (MMCs) [1-11]. Using this methodology the interfacial debond strength of a MMC consisting of a Ti-22Al-23Nb(at.%) matrix alloy embedded with Trimarc silicon-carbon fibres was evaluated. The fibre/matrix debond location was identified to be within the carbon layers at the fibre-matrix interface and the debond strength was found to be almost negligible.
A Fluid-Structure Interaction Model of Pressurised Composite Structures Subjected to Blast Loading
Authors: Mohamed G. , Soutis C. , Hodzic A.
Published: January 2019

A numerical study into the dynamic behaviour of hybrid pressurised barrels manufactured from GLARE (Glass fibre Reinforced laminate) has been performed using the Arbitrary-Lagrangian-Eulerian (ALE) method that accounts for fluid structure interaction within the explicit finite element software RADIOSS. The results high-lighted the importance of the geometrical features of the closed barrel when assessing the shock wave propagation of the blast wave. Also the effect of pre-pressurisation was studied which proved significant in providing additional internal energy to the system. It was concluded that pressurisation should be accounted in all future studies to model the dynamic crack growth and structural integrity of typical aircraft structures subjected to blast.
Experimental and Numerical Buckling Analyses of Laminated Composite Plates under Temperature Effects
Authors: Ergun Emin
Published: January 2019

The aim of this study is to investigate, experimentally and numerically, the change of critical buckling load in composite plates with different ply numbers, orientation angles, stacking sequences and boundary conditions as a function of temperature. Buckling specimens have been removed from the composite plate with glass-fibre reinforcement at [0°]i and [45°]i (i= number of ply). First, the mechanical properties of the composite material were determined at different temperatures, and after that, buckling experiments were done for those temperatures. Then, numerical solutions were obtained by modelling the specimens used in the experiment in the Ansys10 finite elements package software. The experimental and numerical results are in very good agreement with each other. It was found that the values of the buckling load at [0°] on the composite plates are higher than those of other angles. Besides, symmetrical and anti-symmetrical conditions were examined to see the effect of the stacking sequence on buckling and only numerical solutions were obtained. It is seen that the buckling load reaches the highest value when it is symmetrical in the cross-ply stacking sequence and it is anti-symmetrical in the angle-ply stacking sequence.
All-Cellulose Nanocomposite Made from Nanofibrillated Cellulose
Authors: Yousefi Hossein , Nishino Takashi , Faezipour Mehdi , Ebrahimi Ghanbar , Shakeri Alireza , Morimune Seira
Published: January 2019

Commercial microfibrillated cellulose (MFC) was ground and turned into nanofibrillated cellulose (NFC), then all-cellulose nanocomposites (ACNC) were prepared by partially dissolving method. The nanocomposites, with different ratios of undissolved core part of NFC in a matrix of partially dissolved skin part of NFC, were produced using DMAc/LiCl as solvent system. Five dissolution times of 5, 10, 20, 30 and 60 minutes were used as variables and the results were compared with the properties of neat MFC and NFC sheets. The structure and properties of MFC, NFC and nanocomposites were characterized using atomic force microscopy, field emission scanning electron microscopy, X-ray diffraction and tensile tests. The mechanical properties of NFC are significantly larger than those of MFC. As dissolution time increased, the apparent crystallinity of ACNC decreased and more amount of matrix covered the nanofibre surfaces. The ACNC showed best tensile strength (156 MPa) and Young's modulus (13.2 GPa) at 10 minutes dissolution time. The advantage of ACNC is that they are fully bio-based, easily recyclable, fully biodegradable and strong materials.
Improved Compressive Properties of a Unidirectional Cfrp Laminate Using Nanosilica Particles
Authors: Jumahat A. , Soutis C. , Jones F. R. , Hodzic A.
Published: January 2019

The effect of nanosilica particles on the compressive properties of a unidirectional (UD) HTS40/828 carbon fibre reinforced polymer (CFRP) composite was studied. A series of nanomodified CFRP composite was fabricated using 3.6-19.7 vol.% nanosilica-modified epoxy resin. Static uniaxial compression tests were conducted on [0]8 laminate specimens of 12 mm gauge length to evaluate the compressive properties. It was found that the compressive modulus and strength of nanomodified UD system were improved with increasing nanosilica content without any significant reduction in failure strain. The presence of spherical silica nanoparticles stiffened the epoxy matrix and offered a better lateral support to the carbon fibre. Therefore, the compressive properties were improved significantly in comparison with the unmodified CFRP system. These results suggested that the interaction between the nanomodified epoxy and the carbon fibre is very good therefore the load is successfully transferred via the interface to give higher resistance against deformation when it was loaded in compression.
Linearized Material Properties of Nonlinear Interfacial Contact for Layered Composites
Authors: Lord C. E. , Rongong J. A. , Hodzic A.
Published: January 2019

In this paper an analytical model is presented for the prediction of displacement fields for naturally debonded composites. Focused research on the area of naturally debonded composites has resulted in an approach that can be used to efficiently and accurately predict their behaviour under static and dynamic bending conditions. This analytical approach is accomplished through the examination, and the inclusion, of the interfacial kinematics and mechanics.
Preparation and Microwave Absorption Properties of CNTs/Fe3O4 Composite for Hyperthermia Applications
Authors: Aihong Liu
Published: January 2019

In this letter, the surface of carbon nanoutubes was successfully decorated by Fe3O4 via a simple and effective coprecipitation and hydrothermal treatment method. Then the resultant composite were characterized. The results showed that Fe3O4 nanoparticles in the surface of carbon nanotubes were uniform and universal; The composite was ferromagnetic and also had better absorbing properties in the 0-5GHz range. CNTs/Fe3O4 composite had significant potential for electromagnetic wave absorption application in tumor hyperthermia.
Stationary Self-Heating of the Circular and Annular Composite Plates Hinged on the Boundary under Axisymmetric Cyclic Loading
Authors: Katunin Andrzej
Published: January 2019

The present study is focused on the analytical modelling of the stationary self-heating caused by the hysteretic behaviour of the polymeric laminated circular and annular plates hinged on the boundary under axisymmetric transverse cyclic loading. The investigation was based on the complex parameters concept. The coupled thermoviscoelasticity problem was solved by substitution of the dissipation energy function to the heat transfer equation as a source function. The self-heating temperature distributions formulas were obtained by solving the heat transfer equation with appropriate thermal boundary conditions using trigonometric Fourier series. Numerous parametric analyses were presented. It was shown, that omitting the influence of the self-heating effect may results in the incorrect description of the behaviour of polymeric composites under cyclic loading.
The Effect of Sizing Agent of Carbon Fibre on the Interface of Electron Beam Cured Composites
Authors: Bao Jianwen , Li Ye , Zhong Xiangyu , Chen Xiangbao
Published: January 2019

To understand the effect of interface on the properties of electron beam cured composites, the composition and its chemical structure of the sizing agent of carbon fibres were investigated. The results show that there are alkali groups in the sizing agent of T300 and T800 carbon fibres, and these alkali groups react with the strong proton acids that are generated by the initiator and hinder the EB curing of cationic epoxy resin matrices. The properties of the composites of T300 and T800 carbon fibres cured by EB were poor. In the composites of T700, M40 and M40J carbon fibres, the effects of the sizing agent of the carbon fibres on the EB curing and the composite properties are less than for T300 and T800. After the carbon fibres were extracted by acetone, the properties of their composites improved. In particular, the heat-resistance and mechanical properties of composites of T300 and T800 carbon fibre increased greatly.
Modeling of Tensile Modulus of Polyolefin-Layered Silicate Nanocomposites: Modified Halpin Tsai Models
Authors: Mittal Vikas
Published: January 2019

The modified forms of Halpin Tsai model for the prediction of tensile modulus of polyolefin-layered silicate nanocomposites are discussed. The assumptions used in the conventional model like perfect alignment of the particulate filler, uniform shape and size of the filler particles as well as interfacial adhesion between the polymer and filler surface do not hold true in the case of polymer nanocomposites especially using polyolefinic matrices. The modulus reduction factors suggested for polar nanocomposites are also dependent on the polymer nature as well as filler morphology in the composite, thus, are not applicable directly to the polyolefin composites. A master curve could be generated for polyolefin nanocomposites which provided more accurate modulus reduction factor value based on the average aspect ratio of the filler. Incorporation of the effects of incomplete exfoliation as well as filler misalignment though improved the prediction capabilities of the model, however, it still did not match the predictions generated from finite element analysis or TEM analysis. The effect of absence of adhesion forces at the interface was incorporated by suggesting simple modification to the modified Halpin Tsai model equation. Master curves could be generated which predicted the relative tensile modulus of the composites accurately if the value of average aspect ratio was known.
Investigation of Water Diffusion in Triangular Bar-Reinforced Composites
Authors: Pajarito Bryan , Kubouchi Masatoshi , Aoki Saiko
Published: January 2019

This work investigated water diffusion in composites consisting of a permeable matrix reinforced with aligned, impermeable, triangular elements. The triangular elements are expected to induce single axis-, filler orientation-dependent transport behaviour in the composite. Such property is suggested to be useful in slow barrier applications and fast drying processes. To test this idea experimentally, triangular bar-reinforced composite specimens are prepared using thermosetting plastics as representative components. Using water as model diffusant, specimens undergo absorption-desorption-reabsorption gravimetric experiments at 80°C. It is observed that diffusivity decreases when the base side of the reinforced triangular bars is exposed to diffusion and increases when it is the sloped side. Diffusion is also reduced when the triangular bars are in staggered alignment.
Thermoelastic Bending Response of Angel-Ply Composite Plates Resting on Elastic Foundations
Authors: Zenkour Ashraf M. , Abbas Ibrahim A.
Published: January 2019

Different plate theories are presented to study the thermoelastic response of a multilayered angle-ply composite plate. The plate is subjected to a sinusoidal temperature and resting on different types of elastic foundations. The effects due to thermal loads and elastic foundations parameters as well as the variation of lamination angle are studied. Numerical results suggest that Pasternak's model should be used for such plates resting on elastic foundations.
Rheological Properties of Al2O3 Nanoparticle Toughened Epoxy Resins
Authors: Zhang Daijun , Liu Gang , Zhang Hui , Bao Jianwen , Zhang Zhong , Yi Xiaosu , Chen Xiangbao
Published: January 2019

The effect of nanoparticle content on the rheological properties of toughened epoxy resins was studied by measuring the isothermal viscosity-time curves of Al2O3 nanoparticle toughened epoxy resin at different temperatures. The chemorheological properties of toughened epoxy resin systems were analysed using the Dual-Arrhenius equation and a corresponding chemorheological model was established. The model agrees well with the experimental results and provides a theoretical basis for rational development of parameters for Al2O3 nanoparticle toughened epoxy resin based composite molding processes.
Reinforcements of Petroleum Distillation Products with Carbon Nanotubes and Vapour Grown Carbon Fibres for the Development of Carbon Nanocomposites
Authors: Malik Parth , Katyal Varun , Kumar Anil
Published: January 2019

This study reports the synthesis of nanocomposites based on coal tar pitch, a carbon based material retrieved as residue during fractional distillation of petroleum reinforced by multiwalled carbon nanotubes (MWCNTs) and vapour grown carbon fibre (VGCF). With 10% wt. carbon nanotubes slight improvement in flexural strength and modulus is observed, while thermal conductivity increases marginally with 5% wt. carbon nanotubes. However significant improvement of more than 100% in bending strength is observed in vapour grown carbon fibre compounded pitch resin post graphitization at 10% wt. loading as compared to neat resin indicating better load transfer between two phases. Scanning electron micrograph shows that vapour grown carbon fibre are well dispersed in pitch matrix resin. However increasing filler content leads to agglomeration of fibres and voids in the matrix resin.
Measurement System for On-Line Compaction Monitoring of Textile Reaction to Out-of-Plane Impregnation
Authors: Becker D. , Mitschang P.
Published: January 2019

An out-of-plane permeability measurement system for on-line monitoring of textile compaction is presented. It allows accurate correlations of the measured permeability with the current fibre volume content, even when no or few pre-compaction is provided. Also the investigation of hydrodynamic compaction behaviour is possible: Therefore, novel insights on the textile behaviour during out-of-plane impregnation can be gained, which are needed for a cycle time-optimized determination of process and material parameters.
Thermal Residual Stresses in Thermoplastic Composite Disc with Holes Using 3D-Fem
Authors: Sen Faruk , Koruvatan Tuncer , Aldas Kemal
Published: January 2019

In this study thermal residual stresses were calculated for a composite disc with many holes using 3D-FEM. Most of previous studies related to thermal stresses and residual stresses of composite disc were performed as two dimensional, but present study was done using three dimensional modelling and FEM, firstly. The composite disc was thermoplastic matrix and steel fibres for reinforcement material as unidirectional for radial direction. Different uniform temperature distributions were subjected to the thermoplastic composite disc as thermal loads. Finite element method (FEM) was used to compute thermal residual stresses. For this purpose, the thermal stress analysis was carried out in two stages as elastic and elastic-plastic solutions. All modelling and solution processes were done using ANSYS finite element software which is known as a general purpose engineering simulation. According to obtained results, thermal residual stresses in thermoplastic composite disc were created by applied thermal loadings owing to the composite disc having different thermal expansions in radial and tangential directions.
Laminate Thickness Evolution during the Resin Infusion Step of Vartm
Authors: Chen Dingding , Yoon Sangjae , Arakawa Kazuo , Uchino Masakazu
Published: January 2019

The entire infusion step in a vacuum-assisted resin transfer molding (VARTM) process was measured by a three-dimensional digital image correlation (DIC) testing system. The results showed that a stack of fibre reinforcements initially shrank and then expanded as the resin filled the cavities before closing the inlet. The full-field thickness change distribution calculated from 3D DIC revealed zones that were unsaturated, partly saturated, and fully saturated with resin.
Experimental Analysis of Debonding of Skin/Stringer Interfaces under Cyclic Loading and Ageing
Authors: Abbadi Ahmed , Michel Laurent , Castanié Bruno
Published: January 2019

An experimental investigation aiming to characterize the fatigue failure mechanisms and effect of ageing of skin/stringer interfaces is presented. A simplified specimen known as a “stringer foot specimen” is used. The effects of local design, of the angle of plies located at the interface and of moisture ageing are studied. Among other results, it is shown that a quasi-infinite fatigue life can be obtained under 33% of the static damage initiation load for all designs. In the framework of multi-level analysis, this study is a preliminary investigation to study cyclic buckling of composite stiffened structures.
Effects of the Stacking Sequence, Material Nature and Addition of an Adhesive Film on the Delamination Resistance of Woven Composite Laminates in Mode I and II
Authors: Navarro P. , Aubry J. , Pascal F. , Marguet S. , Ferrero J.F. , Dorival O.
Published: January 2019

Woven composites are well-known for their good transverse properties and for their high fracture toughness. The damage mechanisms leading to delamination in woven composites are identified in mode I and II and are compared with those occurring in unidirectional laminates. The influence of several parameters, including the draping sequence and the fibre / matrix interface on the fracture toughness of woven composite laminates is studied. Pure Mode I and Mode II tests are carried out on several carbon/epoxy and glass/epoxy woven composites configurations and the differences observed are discussed from a fractographic point of view. The study illustrates the high fracture toughness of the composites made of woven fabrics as well the influence of the orientation of the plies, the nature of the fibres and the addition of an adhesive film.
Assessment of Liquid Resin Infusion Impregnation Quality Using Scanning Electron Microscopy
Authors: Bourchak Mostefa , Harasani Wail
Published: January 2019

Fibre reinforced composite materials are increasingly becoming the popular choice of materials for designers in many fields such as aircraft manufacturing. As well as the accompanying high costs, one of their main limitations is the difficulty of making shaped parts such as those of aircraft and UAVs. To overcome this problem, various composite manufacturing techniques have been developed including the vacuum resin infusion (VRI) process and its many derivatives. In this work, a cross ply glass fibre reinforced plastic (GFRP) composite laminate was manufactured using liquid resin infusion (LRI) process which is a derivative of VRI. Specimens cut from the manufactured laminate are tested under static tensile loading and then investigated for resin impregnation quality using two types of state of the art Field Emission Scanning Electron Microscopes (FESEM). Images taken showed some plies with well intralaminar (inter fibre within single ply) impregnation whereas in some locations - within mainly the internal plies - there was very little impregnation. The implication is that unidirectional (UD) laminated when stacked in a cross ply form present another LRI process factor that is not widely investigated. Consequently, infusing UD cross ply composite laminates may present more challenges compared to infusing woven fabrics which are helped by the gaps between the fibres weave and weft.
Graphene Oxide – Cardanol Based Polymer Benzoxazine Nanocom-Posite as High Dielectric Strength Material for Electrical Applications
Authors: Sahila S. , Chhonkar Anjali , Jayakumari L.S.
Published: January 2019

Thermally strong and multifunctional cardanol based nanocomposite was synthesized using graphene oxide as nanofiller. Benzoxazine monomer (BZ) was synthesized by using bio-product cardanol, p-Toluidine and formaldehyde. Graphene oxide (GO) was mixed with prepared BZ monomer at different weight percentage and copolymerized with diglycidyl ether of bisphenol-A at different loading level to make copolymer. BZ monomer was characterized by FT-IR, and NMR. GO was characterized by FT-IR, XRD, SEM and TEM. Thermal and electrical properties of Polybenzoxazine-graphene oxide/epoxy (PBZG-EP) nanocomposites were tested. The electrical properties of PBZG-EP were significantly improved compared with those of pure epoxy (EP) matrix. The dielectric strength of PBZG-EP was higher than that of pure epoxy matrix, due to interfacial polarization and intermolecular hydrogen bonding between the GO and the polymer which enhances the dielectric strength of PBZG-EP nanocomposite from 6.6 to 8.16MV/m.
Partial Strain Energy Release Rate for Study Matrix Cracking Evolution in Composite Cross-Ply Laminates
Authors: Rebière Jean-Luc
Published: January 2019

Matrix cracking is generally the first observed damage in composite laminates. The stress field distribution in the damaged cross ply laminates is analysed through an approach which uses several hypotheses to simplify the damage state. The proposed cracking criterion involves the respective partial part of the 0° and 90° layers to the damage process. The initiation of transverse and longitudinal cracking mechanisms is predicted.
Hygric Strain Behaviour of Natural Composites
Authors: Madhusudan S. , Bhargava N.R.M.R , kiran J. Madhu
Published: January 2019

Extracted pineapple and banana fibres are incorporated in polyester resin matrix to prepare pure pineapple and pure banana fibre composites using hand layup technique. For comparison purpose glass fibre composites are also fabricated under similar processing conditions. A separate test setup has been designed for determination of hygric strain (β). All the specimens were subjected to moisture test in order to estimate hygric strain. Specimen deflections were measured periodically with respect to time. All samples are also exposed to the same environment are removed periodically from the water bath and weighed on an analytical balance to determine the relative weight gain, ‘M’. The average moisture concentration ‘C’ is computed using relative weight gain and densities of composite and water. Coefficient of hygric strains are determined from moisture concentration (C) and hygric strains (β).
Effect of Alkali Treatment and Molding Temperature on Flexural and Impact Properties of Coir-Fibre-Epoxy Composite
Authors: Tai C. K. , Ahmad R. , Akil H. M. , Ratnam M. M.
Published: January 2019

The combined effects of alkali treatment and compression molding temperature on the flexural strength and impact resistance of woven coir fibre composites are investigated. Ten pieces of composites plates made from single-layer woven coir fibre fabricated under different process parameters were used in the study. Five pieces of the coir woven fibre were treated with 6% sodium hydroxide (NaOH) solution while another five were left untreated. The compression molding temperature were varied between room temperature (25°C), 50°C, 75°C, 100°C and 125°C. The flexural properties of the composite were evaluated using the three-point flexural test, while the impact resistance was investigated by drop weight impact tests using a specially designed indenter. The indentation radius on each test specimen was measured using a 3-D metrology system and the depth of indentation was determined from the geometry of the indenter. The results show that the maximum flexural load to failure is improved by 38.9% when the fibres were treated and the compression molding temperature is increased to 125°C. The flexural modulus generally decreased with increase in the molding temperature. The depth of indentation in the treated coir woven composites is lower than that of untreated fibre composite at all molding temperatures. The impact resistance of both untreated and treated fibre composites decreased with the increase in the compression molding temperature. Composites fabricated by molding at room temperature, 50°C and 75°C using treated fibre produced the best impact properties.
On the Compression Mechanism of the Composite Lattice Structures
Authors: Jiang Yunpeng
Published: January 2019

The composite lattice structure is regarded as a porous material in the present work, and then the corresponding compression mechanism is clearly interpreted by a simple but reasonable phenomenological model, which containing a damage element to account for the micro-buckling progression and a reinforcement element for the reduction of void volume fraction. Moreover, a micromechanics model is developed to quantitatively characterize the stiffness degradation induced by the micro-buckling deformation. The accuracy of the analytical model is verified by the comparison with experiments.
Ablation Behavior of HfC Coating Prepared by Supersonic Plasma Spraying for SiC-Coated C/C Composites
Authors: Yang Yang , Li Kezhi , Li Hejun
Published: January 2019

In order to improve the ablation resistance of C/C composites HfC coating was deposited on the surface of SiC-coated C/C composites by supersonic atmospheric plasma spraying. The microstructure and morphology of the different coatings were characterized by Scanning Electron Microscopy, X-ray diffraction. The ablation test of samples was carried out with an oxyacetylene torch. The coating exhibits dense structure and good ablation resistance. After ablation for 30s, the linear and mass ablation rates of the coating are 0.59 μm/s and 0.6 mg/s, respectively. In ablation centre region, a HfO2 layer is formed on the surface of sample after 30s ablation, and it can protect C/C composites from ablation.
Alumina Nanoparticles Enhance the Directional Tensile Properties of Glass/Epoxy Composite
Authors: Rajanish M , Nanjundaradhya N V , Sharma Ramesh S , Shivananda H K
Published: January 2019

In this paper, diglycidyl ether of bisphenol A (DGEBA) / triethylene tetramine (TETA) system is used as the starting epoxy matrix and alumina nanoparticles at various concentrations (0.2wt%, 0.4wt%, 0.6wt%, 0.8wt% and 1.0wt%) are employed to modify the epoxy matrix. The UD (unidirectional) glass fibres are used along with the unmodified and modified epoxy resins for fabricating the composite laminates by hand layup process followed by vacuum bagging. The tensile properties of the composite such as tensile strength and tensile modulus are investigated along the longitudinal, transverse direction and also at 45° orientation of fibres using a universal testing machine. From the results, it is found that tensile modulus of the composites was influenced much by the addition nano-fillers while the tensile strength was found to be less altered. Also, the present study showed that nano-modified composites exhibit significantly improved tensile properties along the transverse direction while the properties along the longitudinal direction were not affected much by the nano-fillers due to the dominating effect of the fibres. The maximum enhancement of tensile modulus and tensile strength was found to be 8.85% and 3.72% in the composite having 0.6wt% of alumina nanoparticles in the transverse direction. Further addition of nanoparticles decreased the properties, which were explained with the concept of agglomerations formed by the nanoparticles in the matrix which weakens the mechanical properties. The graphs are employed to explain the results. Hence, to obtain a best possible design, the properties of the fibre reinforced nano-composite laminate at different angles are to be considered as continuous variables in a design process.
Elastic-Plastic Thermal and Residual Stress Analysis of Adhesively Bonded Single Lap Joint
Authors: Sen Faruk
Published: January 2019

In this work, an elastic-plastic thermal and residual stress analysis were performed for adhesively bonded single lap joint. For this purpose, thermoplastic composite adherents were bonded to each other with epoxy adhesive. Thermoplastic composite material was reinforced by steel-fibres, unidirectionally. Finite element method (FEM) was preferred to obtain thermal elastic and elastic-plastic stress distributions on single lap joint. Accordingly, modelling and solution processes were achieved using ANSYS software. So as to determine effects of uniform temperature loadings on thermal and residual stresses, different values of it were loaded on the joint, uniformly. Briefly, both thermal and residual thermal stresses were calculated under uniform temperature loading which was selected from 40 °C to 80 °C. According to obtained results different thermal expansion coefficients of composite adherents and adhesive layer caused thermal and residual stresses on adhesively bonded single lap joint due to applied uniform temperature loadings. Thermal stress values for x and y-directions are very different from each other owing to orthotropic material properties of thermoplastic composite. The magnitudes of elastic analyses results are higher than elastic-plastic analysis results. Contrary to elastic analysis results, elastic-plastic analysis results were nonlinear. Thermal and residual stresses are increased by increasing uniform temperature values, so the highest values were calculated when 80 °C. The plastic yielding was firstly come into being for 50 °C loading and it is expanded related to raising thermal loadings as nonlinear.
Impact of Different Boundary Conditions on the Response of Glare Fiber-Metal Laminates under Lateral Indentation
Authors: Bikakis George S.E. , Savaidis Alexander
Published: January 2019

In this paper, a finite element modelling procedure is implemented in order to predict the static load-indentation curves and the defection shape of simply supported circular GLARE fibre-metal laminates subjected to lateral indentation by a hemispherical indentor. ANSYS software is used and a non-linear analysis is employed with geometric and material non-linearities for FEM calculations. The finite element modelling procedure is applied to GLARE 2–2/1–0.3 and to GLARE 3–3/2–0.4 simply supported circular plates with various diameters. It is found that the simply supported circular GLARE plates deform axisymmetrically from the beginning of the indentation process up to the point of their first failure due to glass-epoxy tensile fracture. By comparison of the obtained load-indentation curves to corresponding previously published load-indentation curves of clamped circular GLARE plates, the effect of the different boundary conditions on their lateral indentation response is studied. Furthermore, the strain energy-indentation curves of the considered circular GLARE 2 and GLARE 3 plates with simply supported and clamped boundaries are calculated and compared. It is found that the simply supported GLARE plates have reduced stiffness and demonstrate an increased first failure defection due to glass-epoxy tensile fracture versus the clamped GLARE plates, whereas the first failure load is not significantly affected by the different boundary conditions. It is also found that for the same lateral indentation, simply supported GLARE plates absorb lower strain energy levels than clamped GLARE plates. Referring to a specific lateral indentation level, the influence of the different boundary support on the corresponding indentation load and the absorbed strain energy is strong and can reach a deviation level of 45 % between the two support types. To our knowledge, a research concerning the response of simply supported GLARE plates under lateral indentation has not been published elsewhere.
A Micro-Fracture Model and its Application in Hardened Cement Paste
Authors: Jin Kan , Wei Cao
Published: January 2019

A micro-fracture model is presented to investigate mechanics properties of porous media such as cement paste on basis of micromechanics theory and fracture theory. Relationships between mechanics properties of porous media and the parameters of pores such as shape, size, and porosity are analysed by this model. Calculation results show that, to a hypothetic porous media with same porosity, the ultimate strength and elastic properties are reduced with an increase of average pore diameter. Nano-scale pores have little effect on the ultimate strength of this porous media while the micron-scale pores have great effect on it. The stress-strain relationship of this porous media with the micron-scaled pores is nonlinear obviously. The results also show that the ultimate strength and elastic properties of the porous media are reduced with an increase of the porosity and shape parameter. Mechanics properties of a cement paste with water cement ratio of 0.5 are tested. The calculation results from the model are in agreement with the experimental results.
Micromechanical Modeling of Damage Development in Polymer Composites
Authors: Arabatti T. , Parambil N. K. , Gururaja S.
Published: January 2019

Damage initiation and progression in long fibre unidirectional continuous polymer composites has been studied at the micro-scale considering a three dimensional repeating unit cell (3D-RUC) with square packing consisting of a single fibre in a polymer matrix. Three damage modes under static loading have been looked at, viz., matrix damage, fibre failure and fibre-matrix debonding. A progressive damage model for the matrix, fibre breakage model using maximum stress failure criterion and interface debonding using a traction-separation criterion via cohesive zone modelling (CZM) approach has been implemented. Homogenization of the said 3D-RUC has been conducted for various load cases that describes the averaged response of the microstructure under combined progressive damage modes.
Electrical Discharge Machining of Metal Matrix Composites with a High Speed Non-Round Electrode
Authors: Liu J.W. , Xiao Y.J. , Guo Z.N. , Wang S.J. , Yue T.M. , Tang Z.W.
Published: January 2019

An electrical discharge machining process with a high electrode rotation speed (EDM-HS) has been developed to solve the problems of the conventional EDM process in machining metal matrix composites (MMCs). The EDM-HS process employs a non-round tool electrode. The experiment results showed that the materials removal rate (MRR) of the workpiece can be improved significantly by employing a non-round tool electrode. The relationship between the pulse duration, machining current, duty cycle, the rotation speed of the tool electrode and the MRR has been studied respectively. And the machining mechanism of this EDM-HS process has been analyzed both theoretically and experimentally. The results showed that the non-round electrode can enlarge the machining gap and with a high electrode rotation speed, the machined debris can be discharge out of the machining area effectively and hence a stable machining condition can be obtained. As a result, a higher MRR can be achieved. Moreover, an orthogonal analysis has been utilized to study the relative importance of the machining parameters on MRR. It was found that to obtain the highest MRR, the electrode rotation speed was the most influential factor among the duty cycle, machining current, pulse duration and electrode rotation speed. This outcome supports that it is feasible to use this novel method to machining particulate reinforced MMCs, where a higher MRR can be achieved.
Synthesis and Characterization of Structure of Fe3O4@Graphene Oxide Nanocomposites
Authors: Fu Ruimin , Zhu Mingfu
Published: January 2019

Nowadays, the hummers method for preparation of graphene oxide (GO) was improved. The grapheme oxide @ Fe3O4 magnetic nanocomposites were synthesized by co-precipitation method. After analysing the morphology and structure of obtained nanocomposites by X-ray diffraction (XRD), transmission electron microscope (TEM) and Fourier transform infrared (FT-IR) spectroscopy, the result was shown as follows. The particle size of Fe3O4 in nanocomposites is 30 nm. Many functional groups are found in grapheme oxide, and such groups could be used to bind with the drug. In the test for magnetic properties, the nanocomposites gathered rapidly in the vicinity of the permanent magnet. The nanocomposites, with high superparamagnetism, can be used in the following applications: drug targeting transports, drug carrier, and diagnosis assistant system.
Influence of Silica Based Carbon Nano Tube Composites in Concrete
Authors: Swamy BLP Dheeraj , Raghavan Vaibhav , Srinivas K , Rao K Narasinga , Lakshmanan Mahadevan , Jayanarayanan K. , Mini K.M.
Published: January 2019

This study focuses on the utilization of highly densified materials in cementitious composites with objectives of improving the mechanical performance and minimizing the number and size of defects. Due to their excellent mechanical properties, carbon nanotubes (CNTs) are now viewed as potential candidate for reinforcement in cement composites. The present paper reports the use of carbon nanotubes (CNTs) as reinforcement to improve the mechanical properties of portland cement paste and creating multifunctional concrete. In order to increase the bonding, and strength, a material with intermediate fineness, highly densified silica fumes, was also utilized. The densified silica fumes along with CNT are added to cement mortar in various proportions. Small-scale specimens were prepared to measure the mechanical properties as a function of nanotube concentration and distribution. Furthermore, properties like shrinkage, permeability and alkalinity of the resultant composite were also investigated. The study addresses the significance of CNT as an additive to the enhancement of properties of cement composite.
Comparison of Domestic and Overseas Graphite/Antimony Composites and Exploration into Their Antimony-Infiltrating Technology
Authors: Xiao-chuan LI , Dong-Xue Wang , Qi-li Wang , Qi Liu , Ya-fei HU , Min HE
Published: January 2019

The technique of pressure-infiltrated antimony in porous graphite can produce sophisticated graphite seal materials. A single batch of samples of graphite/antimony matrix exhibits the differences and disparity in impregnation technology among products manufactured in the US, Japan, and China. In this study, a comprehensive analysis is conducted on the appearance, metallographic microstructure, and physical properties of these graphite/antimony composites. The results indicate that the technology of vacuum pumping before exerting high pressure has been adopted in Japan; this technique is key to removing the isopiestic layer caused by the sheer exertion of high pressure. A method has been proposed by American research where alloying is performed to raise the impregnation rate of large-scale, porous matrix by enhancing the fluidity of molten metal. However, this method cannot eliminate the air's shrinkage cavity and back-pressure and is therefore unable to achieve adequate, comprehensive performance. In China, a technological bottleneck should be investigated to improve the impregnation technology of vacuum pumping before exerting high pressure.
Combined Effects of Chopped Carbon and Glass Fibres on Mechanical Properties of Lime-Based Mortar
Authors: Seker Burcin S. , Cakir Ferit , Acar Volkan , Seydibeyoglu Mehmet O. , Akbulut Hamit
Published: January 2019

Lime-based mortars have been used as bonding materials between stones or bricks since ancient times. It is an integral part of many structures and generally is used to fill the gaps between construction blocks (mortar joint) and strengthen the structures. Nowadays, different organic and inorganic substances are added to mortars in order to improve their physical and mechanical properties. This study deals with the combined effects of chopped carbon and glass fibres on mechanical properties of hydraulic lime-based mortar. Accordingly, lime-based mortar is prepared and chopped carbon (CCF) and glass (CGF) fibres are used as reinforcing materials in the lime-based mortar (1% by plain mortar weight). Five different combinations are investigated: Mixture-1 (100% CCF + 0% CGF), Mixture-2 (75% CCF + 25% CGF), Mixture-3 (50% CCF + 50% CGF), Mixture-4 (25% CCF + 75% CGF), Mixture-5 (0% CCF + 100% CGF). After reinforcing process, mechanical characterization tests are conducted on the mixtures at the end of 28 days curing. In the second stage, scanning electron microscope (SEM) observations and high definition visual inspection are carried out in order to investigate the interface mechanism between fibres and mortar. In the third stage, one-way analysis of variance (ANOVA) is performed to see whether differences between mechanical properties are statistically significant.
Preparation and Properties of Graphite/Antimony Composites Based on Coal Tar Pitch
Authors: Wang Qili , He Min , Li Xiaochuan , Hao Li
Published: January 2019

Coal tar pitch is used as the raw material to prepare graphite/antimony composites, of which the mechanical performance, microstructure, element composition and tribological performance are investigated. Results indicate that the composite density, shore hardness, flexural strength, compression strength and porosity are 2.38g/cm3,103.10Hs,91.65MPa,290.5MPa, and 0.65% respectively, representing physical property improvement of 17.65%-28.75%. In addition to C, the major composite elements are Sb, Si, Al and S, with relative amounts of 87.8%, 4.5%, 3.1% and 2.4%, respectively. Under experimental conditions, the average value friction coefficient is 0.120–0.158. The friction coefficient ranges from 0.08 to 0.149, when the load is 10–48MPa.the friction coefficient decreases gradually as the load increases. The average friction coefficient is equal to 0.141 and 0.114 when the rotating speed is equal to 200r/min and 500r/min, respectively; the friction coefficients declines gradually as rotating speed increases.