Lightweight Composite Materials Research Articles

Stochastic Micro-Meso Modeling of Cross-Ply Composites for Prediction of Softening

Composites are extensively using in modern industry (aircraft and automobile manufacturing, construction, etc.). Nowadays high-strength and lightweight composite materials, such as FRPs, exhibit elastic and strength anisotropy and deform nonlinearly at high stresses. Also, such materials have small enough failure strain in comparison with metals, and they are drastically more expensive than steel and aluminum alloys. The most important task in the design of structures made of composite materials is the minimization of its weight without loss of strength properties. We presented the method for modeling a UD FRP with randomly arranged fibers at the micro-and meso-level. These two approaches were compared on the problem of the composite panel tension. The selection of the mesomodel mechanical characteristics was based on data of the micro-level model. In the mesomodel, the damage accumulation of middle layer (90° layer) was simulated using the Stochastic Failure criterion (random Mott scatter of layer strength). The calculated curves and data, obtained in micro-and mesomodels, correlate well with each other.

Synthesis of Cyanate Ester Based Thermoset Resin by Using Copper (II) Oxalate as Catalyst and its Application in Carbon Fiber Composites

Polymer matrix plays a crucial role in the development of advanced light weight composite materials, and is mainly responsible for thermal and mechanical properties. These polymer matrices are usually thermosetting plastics due to their ease of processing. Thermoset resins were prepared using different compositions of dicyanate ester of bisphenol A and polyether imide and carbon fiber laminates were prepared by wet layup technique. Small amount of epoxy (diglycidyl ether of bisphenol A) was also added to the composites to improve the (interfacial) bonding between the carbon fiber and the resin. The Copper (II) oxalate with 1,5-pentanediol was used as a catalyst for the first time to reduce the curing time from eight hours to four hours. The catalyst has also reduced the curing temperature from 400°C to 250°C. The catalyst Copper (II) oxalate is commercially available. The plasticizer has improved the thermal and mechanical properties of the matrix significantly. The addition of epoxy to the thermoset resin improved the (interfacial) bonding between the resin and carbon fiber. FTIR results suggest that the polymerization reaction of dicyanate results in the formation of trizine ring with phenolic group. SEM results show the interaction of bisphenol A dicyanate (BPADCy) monomer to form polymer matrix. SEM images also represent a uniform anchoring of matrix on the individual carbon filament. It is clear from thermal analysis that sample having 85% BPADCy and 15% polyetherimide (BPR-2) shows the greater thermal stability which is due to the reaction of epoxy with cyanate matrix.

Effect of fiber surface treatment on structure, moisture absorption and mechanical properties of luffa sponge fiber bundles

Luffa sponge (LS) is a resourceful natural plant fiber with polyporous structure, which can be effectively used for reinforcement of light weight composite materials. However, reduction in the moisture absorption tendency and enhancement in the mechanical properties of LS fiber bundles by chemical modifications are highly desirable in order to utilize LS as reinforcement material. In this study, three chemical treatments including the use of 5% sodium hydroxide and 5% hydrogen peroxide (5%NaOH-5%H2O2), 10% NaOH and 20% acetic acid (10%NaOH-20%CH3COOH), and 18% NaOH and 1.6% carbamide (18%NaOH-1.6%CO(NH2)2) were used to modify the LS fiber bundles. And the effect of the three chemical treatment methods on the micro/nano structures, moisture absorption and mechanical properties of LS fiber bundles was investigated by using scanning electron microscopy (SEM), transmission electron microscopy (TEM), polarized light microscopy (PLM), fourier transform infrared spectroscopy (FTIR), X-ray diffraction analysis, moisture regain (MR) and tensile strength test. The results showed that the treatment with 10%NaOH-20%CH3COOH could significantly improve the mechanical properties of LS fiber bundles, the increase of the tensile strength was 121.3%. However, the treatment with 5%NaOH-5%H2O2 could sharply decrease the mechanical properties of fiber bundles, the reduction of the tensile strength was 75.0%. Furthermore, the treatment with all the three above mentioned chemical combinations could reduce the moisture absorption of LS fiber bundles. The decrease in the moisture regain was found to be 29.0, 16.9, and 12.4%, respectively.

Optimal Manufacture Formulas for Waste Tire after Pyrolysis and Lightweight Composites after its Combustion Utilization in Sequence through Statically Analyses

The present research will be included in molding condition of temperature, pressure etc. in addition to heat of combustion test and improve strength of the Lightweight Composites by the adhesives with waste tire after pyrolysis. The results can serve as a reference to the Waste tire pyrolysis ash Lightweight Composites by production process design. Basically, take extrusion molding technique and sintering, the Lightweight Composites are produced for the ash from the Waste tire pyrolysis after combustion utilization. This study uses the Taguchi Methods to find the best formula, from product performance analysis and process technology manufacturing, The Lightweight composite material meets the expectations of the commercial market, As a reference for future research. This study use three variable, include adhesive, molding temperature, molding pressure .In the choice of adhesive, the study selected chemically modified starch adhesive, Melamine - urea - formaldehyde co - condensation resin, Isocyanate adhesives. This study was learned by Taguchi rule, the best formula for the Isocyanate adhesives, molding temperature at 135°C, molding pressure at 3.5kg/cm2. In the above conditions made by the lightweight composite material, with excellent bending strength and water resistance, In the fire performance on the more traditional wood-plastic board. From the commercial market point of view, the lightweight composite materials not only have the characteristics of fire resistance, good bending resistance, waterproof characteristics. In the material cost, because the processing technology to enhance, effectively reduce manufacturing costs, more commercial market competitiveness.

Measurement Analysis for Increasing Resource Efficiency during Autoclave Processes for the Production of Fiber Composites

Fiber-reinforced plastics are known as outstanding lightweight composite material, which are used in various areas. Especially the demand for components made of carbon fiber reinforced plastics (CFRP) has steadily increased within the last years due to their high strength and stiffness combined with light weight. The manufacturing of CFRP components is a cost-intensive and time-consuming process due to frequently required and challenging manual operations for several working steps. In order to remain competitive and meet the small-batch production because of increasing desire for individuality and diversity, the manufacturing process of CFRP components needs further development. In order to face these challenges, this paper focuses on the resource efficiency of curing processes with the autoclave technology. The measurement analysis of the different energy consumers of the autoclave at changing the curing parameters (temperature, pressure, time) shows how the settings affect the resource efficiency of curing processes. Finally, the authors present their recommendation for action in order to increase resource efficiency.

Dynamic compressive response of a developed polymer composite at different strain rates

Compressive mechanical response of a developed polymer composite material over a wide strain rate range of 0.0001/s-8000/s is investigated. The developed polymer composite material shows the following stress-strain relation under high rate compressive loading : linear elasticity to a high yield stress, softening behavior with a slight stress decrease, plateau stress accompanied by a large plasticity and densification with a stress increase. Rate dependency of mechanical properties is revealed quantificationally, which follows a power law function. By designing the impact energy (or initial loading rate) in experimental tests conducted by split Hopkinson pressure bar (SHPB), the deformation-to-fracture process related with the inputted strain energy density or with deformation strain during a dynamic loading is observed through the post-test analyses. The ductile damage and brittle fracture characteristics as well as the tolerant cracking mechanisms are illustrated. This work is full of interest to develop a light-weight transparent protective polymer composite material against a high-speed impact loading .

A review of porous lightweight composite materials for electromagnetic interference shielding

Abstract Lightweight porous materials for electromagnetic interference (EMI) shielding applications are reviewed. EMI shielding refers to the capability of a material to protect from electromagnetic fields (EMFs) generated by electronic devices. Traditionally conducting metals are used in EMI shielding applications, which are slowly being replaced by conducting polymer based shields. This review is narrowly focused on understanding the approaches related to porous high EMI shielding composite materials that have very low density values. While metallic fillers can increase the EMI shielding capabilities of polymers, they also increase the weight, which can be offset by inducing the porosity in the matrix. Porosity is found to be effective in providing higher shielding effectiveness at low filler volume fraction due to concentrating the filler in the solid polymers. However, use of gas porosity results in composites with low mechanical properties. This problem can be alleviated to some extent by reinforcing polymer foams with lightweight conductivefillers such as carbon nanofibers (CNFs), carbon nanotubes (CNTs) and graphene. But the properties of pores such aspore size and distribution cannot be effectively controlled in such cases. Syntactic foams containing hollow particle fillers seem to be the best combination of EMI shielding capabilities and mechanical properties. These composites can be either filled with a second phase conducting filler, or hollow particles can be coated with a conducting layer, or hollow particles made of conducting materials can be used as fillers. The hollow particle wall thickness and volume fractions can be optimized to obtain the desired combination of properties in syntactic foams to enable their multifunctional applications.

Carbon fiber/epoxy matrix composite interphases modified with cellulose nanocrystals

Cellulose nanocrystals (CNCs) were used to modify the interphase between carbon fiber (CF) and an epoxy matrix to simultaneously strengthen and toughen the CF composite. CNCs were functionalized with 3-aminopropyltriethoxysilane (APTES) and surface modification was confirmed by Fourier transform infrared (FTIR) spectroscopy and X-ray photoelectron spectroscopy (XPS), which revealed the presence of the new chemical species. Functionalized CNCs (APTES-CNCs) were applied as part of a sizing to coat CFs and an optimum concentration was identified. Single fiber fragmentation tests (SFFT) showed that stronger adhesion between the CFs and the epoxy matrix was achieved for the fibers sized with APTES-CNCs, compared to unsized CFs and epoxy-only sized CFs. CFs sized with APTES-CNCs at a concentration of 1.0 wt% resulted in 81% increase in interfacial shear strength (IFSS) compared to unsized CFs, and the birefringent stress pattern seen during the SFFT supports the assumption that adding APTES-CNCs at the composite interphase promotes an improvement in the failure mode. These results demonstrate that sizing CFs with APTES-CNCs is an effective method to increase the interfacial properties in CF reinforced epoxy composites, and a potential approach for the development of ecofriendly and lightweight composite materials for aerospace and automotive applications.

MANUFACTURING METHOD OF BRAMHA RESIN AND CARBON COMOSITE LAMINATES FOR VARIOUS QUALIFICATION TESTS

At present Carbon/Glass fiber composite structure are widely used with Epoxy Resin. Epoxy resin is employedn primarilyn forn fabricatingn highn performancen composites with bestn physical properties, corrosion properties, superior electrical properties, smartn performancen atn elevatedn temperatures, smartn adhesionn ton a substraten orn an combinationn ofn these edges. Epoxy resins are used with variety of fibrous reinforcing materials as well as glass, carbon. Epoxies are compatible with most composite producing processes significantly various types of molding, filament winding and hand lay-up. nnnn Light weight and high strength composite material thus made promotes aerospace and missile industries to replace metallic structure. However, there are limitations on their use in thermal environment having maximum temperature range of 120-1500C. Also glass fiber composites are subject to considerable water absorption. This limitation is imposed by Epoxy matrix in composite structure. A new indigenous herbal matrix/resin named ‘BRAMHA' has been developed for fabrication of glass/carbon fiber reinforced composite materials. Since it is made from wheat, cereals, proteins, starch mixed with natural gum, it is categorized as “Herbal” resin. Vacuum Assisted Resin Transfer molding (VARTM) composite fabrication process is used for preparation of carbon a glass fiber laminates. This resin is then compared with epoxy for its various physical a mechanical properties such as pure resin shear strength, water absorption, and sand erosion. The strength tests like tensile at room and at elevated temperatures; compression test and inter-laminar shear strength are conducted. The test results obtained show that BRAMHA resin has superior properties than presently used Epoxy resin .The above tests are carried out at Advanced Composite Division (ACD) National Aerospace Laboratory (NAL) Bangalore and Composite Research Center (CRC) DRDO-R a D E, Pune

Comparrative tensile behaviour study of locally developed jute reinforced composite materials with conventional composite materials

The utilization of low cost, lightweight and high heat resistant composite materials is capturing more and more interest from advanced manufacturing industries. These industries are focusing on new type of advanced composite materials like textile composites for applications in aerodynamics systems, fluid dynamics systems, sport cars, wind energy defence integrated antennas (within soldier’s garment and armours for ballistic protection), transportation, construction, power generation sectors, rail, automobile, machine manufacturing etc. In this research, the composite sample specimens were developed under VARTM system by using JF 0/90° oriented as reinforcement agent with matrix material V.E. The developed sample specimens were tested to study comparative tensile behaviour with conventional composite materials. The result reflects that the developed specimen acquires major enhancement in tensile properties such as Tensile strength (Gpa) was improved in the range of 122.95–279.80%, Modulus of Elasticity [MOE (GPa)] was increased by 142.91–228.91%, Break Elongation was raise (%) by 289.90–425.90% and Shear Modulus (C) was enhanced from 846.69 to 1354.71%. During this do research it was also observed that the developed material was of ductile nature, and acquired significant enhancement in mechanical properties against closely related developed composite materials.

Surface decoration of short-cut polyimide fibers with multi-walled carbon nanotubes and their application for reinforcement of lightweight PC/ABS composites

The surface decoration of short-cut polyimide (PI) fibers with multi-walled carbon nanotubes (MWCNTs) was performed by fabricating a polydopamine (PDA) coating layer on the fiber surface and then immobilizing MWCNTs onto the coating layer via covalent bonding. This successful surface decoration was confirmed by scanning electron microscopy, X-ray photoelectron spectroscopy, Fourier-transform infrared microscopy and static water contact angle. The application of the surface-decorated PI fibers as reinforcing fibers for reinforcement of polycarbonate (PC)/acrylonitrile–butadiene–styrene copolymer (ABS) alloy was investigated, which indicated that the MWCNTs-decorated PI fibers not only could effectively reinforce the PC/ABS alloy but also generated a significant lightweighting effect on the resulting composites. The maximum mechanical properties were achieved for the composites at a fiber content of 20 wt.% and a fiber length of 3 mm. This significant reinforcement effect is attributed to the enhancement of interaction bonding strength between the fibers and matrix as a result of the surface decoration of PI fibers with MWCNTs. The morphological investigation suggested that fiber rupture was the major energy dissipation mechanism in the tensile and impact failures, whereas fiber debonding and pullout were partly involved in the fracture energy dissipation. In addition, the presence of surface-decorated PI fibers slightly enhanced the thermal stability and load bearing capability of composites. This work can provide a type of high-performance lightweight composite material for automobile and aviation industries.

Emerging composite material use in current electric vehicle: A review

Today composite has been dominant emerging materials widely using in aerospace, automotive, marine industries. Worldwide automobile transportation and industry have been growing at the fast rate in past few decades especially in urban area. Current IC vehicles are creating a hung amount of pollution due to lower efficiency and heavyweight in road transportation sector. Therefore global automotive industry shifts towards the lightweight composite materials used for vehicles fabrication. Composites materials are more popular in automobile industries because of its lightweight, long life, superior physical, mechanical (i.e. fatigue resistant) properties and it can easily be molded in any shape as compared to traditional metals. As the customer awareness has increased over time, researchers are giving emphasis to automotive light weighting. Few advanced composites materials are relatively more expensive than metals and its selection will depend on the basis of a tradeoff between the cost and performance. This research paper focuses on recent trends in emerging composite material used in automotive industry at present time and its effects on the global automotive market is also discussed. However, the global demand for carbon saving and green mobility is fulfilled by the use of composite material in automation sector. Furthermore, recommendations for future research priorities to overcome these challenges and problems are presented..

Investigation of punch resistance of the Allomyrira dichtoloma beetle forewing

In this study, the punch resistance of the beetle forewing was investigated to address the ability of the forewing against the external force. The punch resistance of the forewing was measured for different sizes and sexes of beetles using a conventional testing method in conjunction with the Digital Image Correlation (DIC) technique. The results showed that the maximum fracture load was measured around 23 N for the female beetle and around 20.2 N for the male beetle in the front-side punch test. Moreover, the fracture load in the front-side punch test was higher than that in the back-side punch test for both male and female beetles. This means that the beetle forewing plays a protection role against external loads. Furthermore, the puncture energy in the front-side punch test for the female beetle (6.91 mJ) was a little higher than that for the male beetle (5.27 mJ). In addition, the DIC results revealed that the first crack occurred along the trachea line and the second crack then appeared in the direction that was perpendicular to the direction of the first crack. This study provides a comprehensive understanding of the mechanical protection properties of the beetle forewing and offers a good lesson for studying lightweight bio-inspired composite material.

Mechanical Characterization and Vibration Analysis of Hybrid E-glass/Bagasse Fiber Polyester Composites

This study is concerned with the mechanical properties like tensile strength, flexural strength, density, hardness and vibration properties of the hybrid sandwich type composite plates made from E-glass/bagasse and unsaturated polyester resin GP-7150 experimentally as well as using finite element analysis Hybrid composite plates were prepared by hand lay-up method with 3%, 6%, 9%, 12%, and 15% weight of bagasse natural fiber. Alkaline treatment of bagasse fiber was done by dipping it in 5% aqueous NaOH solution for 72hours. This results in the removal of a certain amount of wax, lignin, and oils covering the exterior of fiber cell wall which ultimately increases surface roughness resulting into better bonding between fiber and resin. Chemically treated bagasse fibers were then mixed with E-glass fibers in the unsaturated polyester matrix. Samples were prepared by keeping variable bagasse fiber and polyester resin content with constant E-glass fiber content. It was observed that increase in bagasse fiber content was accompanied by the improvement in mechanical properties with 9% bagasse fiber plate showing the best set of properties. Vibrational analysis of hybrid composite plates reveals that highest natural frequency of vibration was found for 9% bagasse fiber plate resulting into best vibrational properties. The decrease in mechanical properties beyond 9% of fiber content can be accounted for the insufficient amount of resin. Also, it has been observed that addition of fiber leads to decrease in density of composite plate due to the inherent low density of bagasse fiber than the polyester matrix. To make lightweight and cost effective hybrid composite material which can be used in lightweight structural applications is the main objective of this study.

Failure analysis of single-bolted joint for lightweight composite laminates and metal plate

A three-dimensional progressive damage model was developed in ANSYS to predict the damage accumulation of single bolted joint in composite laminates under in-plane tensile loading. First, we describe the formulation and algorithm of this model. Second, we calculate the failure loads of the joint in fibre reinforced epoxy laminated composite plates and compare it with the experiment results, which validates that our model can appropriately simulate the ultimate tensile strength of the joints and the whole process of failure of structure. Finally, this model is applied to study the failure process of the light-weight composite material (USN125). The study also has a great potential to provide a strong basis for bolted joints design in composite Laminates as well as a simple tool for comparing different laminate geometries and bolt arrangements.

Fracture Analysis for Attaching Fiber Reinforced Composite on V-Notch Wedge Structure

Sharp V-notches with various angles often appear in engineering structures. When being loaded, the high stress at the apex could result in crack propagation on the structure and further fracture. For this reason, safety evaluation should be emphasized for products or engineering structures with such geometric characteristics. Sharp V-notches are regarded as wedge structures that the above situations seriously and often appear on brittle materials. Regarding the stress intensity factor K of the driving force for wedge structure failure, Chen, Dunn, and Seweryn, with numerical analysis for the fracture experiment, explained that the critical stress intensity factor Kc for single isotropic material fracture could be the intensity failure specification for wedge structures. Nevertheless, V-notched brittle materials are likely to receive great stress over the surface elastic energy of the structure when being loaded, causing brittle failure at the apex. When the high-strength and light-weight composite material is attached to reinforce the surface of brittle materials, the energy is reinforced to enhance the critical stress intensity factor of the overall structure, aiming to improve the failure of brittle materials resulted from stress singularity. This paper therefore tends to discuss the effects of the composite attachment, layer, and fiber reinforced direction on the critical stress intensity factor when the structure is being fractured.

Collapsed carbon nanotubes as building blocks for high-performance thermal materials

The influence of collapsed shape on the thermal transport of carbon nanotubes is studied by nonequilibrium molecular dynamics. Nanotubes of different lengths, diameters, chiralities, and degrees of twist are simulated in the regime in which the thermal transport extends from ballistic to diffusive. In contrast with graphene nanoribbons, which are known to exhibit substantial rough-edge and cross-plain phonon scatterings, the collapsed tubes preserve the quasiballistic phononic transport encountered in cylindrical nanotubes. Stacked-collapsed nanotube architectures, closely related with the strain-induced aligned tubes occurring in stretched nanotube sheets, are shown to inherit the ultrahigh thermal conductivities of individual tubes, and are therefore proposed to form highways for efficient heat transport in lightweight composite materials.

Silane-Treated Basalt Fiber⁻Reinforced Poly(butylene succinate) Biocomposites: Interfacial Crystallization and Tensile Properties.

In this work, an economical modifier silane agent—KH550—was used for surface treatment of basalt fiber. Then, a biodegradable poly(butylene succinate) (PBS)/modified basalt fiber (MBF) biocomposite was successfully developed. The effects of silane treatment and fiber mass content on crystalline structure, isothermal crystallization process and mechanical performance of composites were evaluated. The interfacial crystallization of PBS on the surface of MBF was investigated by using a polarized optical microscope (POM). The transcrystalline (TC) structure could be clearly observed and it grew perpendicular to the surface of MBF, which boosted the nucleation ability on PBS crystallization and the strong interfacial interaction between PBS and silane-treated basalt fiber. Under isothermal crystallization kinetics, the incorporation of basalt fiber enhanced the crystallization rate and reduced the crystallization half-time values of composites compared with that of neat PBS due to a heterogeneous nucleation effect. Furthermore, tensile results confirmed that the presence of MBF could greatly improve the tensile strength and modulus. The predicted interfacial shear strength (IFSS) suggested that an enhancement of interfacial bonding could be realized via interfacial crystallization, which was also verified by SEM images. The PBS/MBF biocomposites can be applied in many fields as a low-cost, lightweight, and biodegradable composite material.

Facile fabrication of superhydrophobic, mechanically strong multifunctional silica-based aerogels at benign temperature

We first reported the simultaneous in-situ amine-modification and hydrophobization of a native silica aerogel at the benign temperature of 0°C for further isocyanate cross-linking, compared with the traditional method at the harsh temperature of −77°C. The hydrolysis of tetraethylorthosilicate (TEOS) was slower than that of tetramethoxysilane (TMOS) and each methyltrimethoxysilane (MTMS) monomer had one non-hydrolyzable methyl group. The hydrophobicity of the native silica aerogels could be adjusted by tunning the MTMS/TEOS molar ratio. The 3-aminopropyltriethoxysilane (APTES) was used to provide a flexible linking group in the silica structure, while the amine group in APTES was further used as a reactive site for reacting with the isocyanate. As a result, a lightweight, mechanically strong and porous silica-based composite material was obtained by encapsulating the skeletal framework of amine-modified silica aerogels with isocyanate.

Facile synthesis and excellent electromagnetic wave absorption properties of flower-like porous RGO/PANI/Cu2O nanocomposites

Novel porous ternary nanocomposite systems containing reduced graphene oxide (RGO)/polyaniline (PANI)/cuprous oxide (Cu2O) were prepared via one-step in situ redox method. The RGO/PANI/Cu2O nanocomposites present a flower-like structure with an average size of 2.0 μm in diameter. The morphologies and properties of the products can be controlled by adjusting the molar ratios of aniline to Cu2+. When the molar ratio of aniline to Cu2+ is 1:1, the product exhibits excellent microwave absorption property in the frequency range of 2–18 GHz. It can be seen that the maximum reflection loss (RL) of the ternary composite is up to −52.8 dB at 2.7 GHz with a thickness of only 2 mm, and the absorption bandwidth corresponding to −10 dB (90% of EM wave absorption) is 13.2 GHz. The microwave absorption property of ternary RGO/PANI/Cu2O composite is significantly improved due to its special flower-like porous structure, dielectric loss property and well impedance matching characteristics, which is 8.12 times than that of pure RGO and 5.28 times than that of pure PANI. Therefore, our study paves a new way to prepare the promising lightweight and high-performance composite materials combined with the characteristics of three components for electromagnetic absorption.