Tensile Properties Of Composites Research Articles

Agricultural-waste Sesamum indicum L./recycled-low density polyethylene bio-composites: Impact of gamma radiation on mechanical and thermal properties

Composites synthesized from natural waste and recycled plastic is quite a promising and interesting field for scientists and polymer industries. In the present study, bio-composites based on agriculture residue Sesamum indicum L. and recycled-low density polyethylene were synthesized by extrusion and injection molding technique at a fiber loading of 10–40 wt%. Additionally, 3% of maleic anhydride grafted low density polyethylene was used as a compatibilizer. The prepared composites were irradiated at 25 kGy, 75 kGy and 125 kGy doses of gamma rays. The effects of different fiber content and gamma doses on mechanical properties were studied statistically by Design Expert software. Response surface methodology was employed to depict the interaction among various factors and optimization was done by desirability index method. Findings indicated that composites having 30% Sesamum indicum L. irradiated at 125 kGy demonstrated best mechanical properties. A significant enhancement in tensile and flexural properties of irradiated composites can be explained effectively in terms of the cross-linking effect. The fiber–matrix adhesion and modifications in composite structure was characterized by fourier transform infrared spectroscopy (FTIR), Scanning electron microscopy (SEM), and X-Ray diffraction (XRD) analysis. Furthermore, thermal stability of the composites was also found to be increased. In addition, gamma-irradiated composite exhibited the highest storage modulus and a decrease in mechanical loss factor was also observed.

Crystal structures of polyamide 6 at the interphase and around carbon fiber and mechanical properties of their composites

This study reports the effect of the polyamide 6 (PA6) crystal structure at the interphase and around the carbon fiber (CF) on the mechanical properties of CF-reinforced PA6 composites. The transverse tensile properties of the unidirectional composites and the four-point bending properties of the quasi-isotropic composites were investigated using three types of CFs. Raman spectra of PA6 were measured to characterize the crystal structures of PA6 at the interphase and around the CFs. The results showed that higher α-crystal (the most thermodynamically stable crystal) content of PA6 at the interphase compared to β-crystal (mesophase) and γ-crystal (thermodynamically metastable) contributed to greater transverse tensile strength of unidirectional composites. Furthermore, it was demonstrated that the flexural strength of the quasi-isotropic composites increased in the case of small variations in the distribution of each crystal structure (α-, β-, and γ-crystal structures) around the CFs. This study provides a framework for the PA6 crystals around CFs to reflect the superior properties of CFs in PA6/CF composites.

Fiber architecture effect on tensile and compressive damage mechanisms of 3D angle-interlock woven composites

Due to the intricate fiber architecture of 3D textile composites, understanding their failure mechanisms presents a challenge. Here we experimentally studied the quasi-static tensile and compressive properties of 3D angle-interlock woven composites (3D AWC) under both warp-loading (AWC-warp) and weft-loading (AWC-weft). Damage morphologies and mechanisms were examined using optical microscopy and X-ray computed tomography. In order to demonstrate the effect of fiber architecture, the results were combined and compared with that of unidirectional (UD) composites with the same total fiber volume fraction (FVF). The fiber architecture effects in 3D AWC can be manifested as the on-axis FVF dependency and fiber undulation influence. When on-axis load-bearing fiber is undulating-free, the difference in mechanical properties is primarily determined by the on-axis FVF. However, the presence of fiber undulation can further weaken the mechanical properties. Moreover, for AWC-warp specimens, fiber undulation has a significant impact on the modes and characteristics of damage, resulting in fiber breakages and kinks that primarily occur in the connection region of warp yarns.

The effects of nano-alumina particles on the enrichment of tensile, flexural and impact properties of carbon fiber-reinforced epoxy composites

An experimental investigation to determine how the mechanical properties of carbon fiber-reinforced epoxy-based composites with alumina nanoparticles are affected by the fiber and filler materials. The analysis used a digital Universal Testing Machine (UTM) and an impact tester. The weight percentage of nano alumina particles are 1, 2, 3, 4, and 5. Besides, the carbon fiber contents are varied as 34, 33, 32, 31, and 30 wt%, respectively. The hand layup technique fabricated the hybrid composite. The epoxy resin matrix was kept constant (65%). All the test specimens analyze through ASTM standards. The tensile strength, flexural strength, impact strength, and water absorption percentages of all fabricated hybrid composites observed between 59.51 and 78.45 MPa, 38.68–50.99 MPa, 12.12–16.81 kJ/m2 and 1.92–2.17% respectively. The manufactured composite specimens' mechanical properties increase with the weight percentage of the filler particles. An additional quantity of filler (3, 4, and 5 wt%) substances in the epoxy matrix caused a reduction of mechanical properties. Experiment results show that increasing the amount of nano alumina particles in composites leads to notable improvements in the fabricated composites' tensile, flexural, impact, and water absorption capability. These mechanical property enhancements increase from the epoxy resin matrix to the carbon fiber and alumina nanoparticles. The outcome of strong bonding connections between the fiber and matrix demonstrates the developed resistance to thread draw out about fiber-reinforced composites lacking nano alumina particles.

Research on Mechanical Properties of Domestic T700S Carbon Fibers

Two types of domestic T700S carbon fibers (CF1 and CF2) were investigated in three batches to find out their mechanical properties, including tensile properties of multifilament, tensile and bending properties of composites. The results showed that the mechanical properties of domestic T700S CF are comparable to those of Toray T700S CF with a small discrete coefficient obtained from experiments for the three batches of CF, and that the unidirectional CF2 composite laminates has the biggest tensile strength discrete coefficient, 3.84%. The difference of properties between the two types of fiber composites was analyzed using the optical contact angle measuring device. It was found that CF2 and resin have better wettability. The two types of carbon fibers were examined by the Ø150 mm standard pressure vessel. Temperature (high temperature, low temperature, and temperature impact) tests and aging tests revealed that: high temperature, low temperature, and temperature impact have little effect on the characteristic index of the pressure vessel; after 800h aging, the characteristic index of the pressure vessel decreased by 15.2%.

Effect of Elevated Temperature on the Behavior of Amorphous Metallic Fibre-Reinforced Cement and Geopolymer Composites

To improve the tensile, flexural, and ductility properties of geopolymer composites, amorphous metallic fibres (AMF) are used to reinforce these composites, and the behavior of these composites at elevated temperatures has been assessed in this study. Four types of composites, i.e., cement, reinforced cement, geopolymer, and reinforced geopolymer composites have been prepared. The composites have been reinforced using AMF with a fibre volume fraction of 0.75%. The composites have been assessed for change in mass loss, cracking, compressive strength, and flexural strength at four elevated temperatures of 200 °C, 400 °C, 600 °C, and 800 °C, and conclusions have been drawn concerning these composites. The results have shown that an increase in temperature has an adverse effect on these composites, and geopolymer composites exhibit higher performance than their counterpart cement composites at elevated temperatures. The mass loss and surface cracking were significantly lower in geopolymer composites, and the fibre reinforcement had a negligible effect on mass loss. Also, the residual compressive and flexural strength of reinforced geopolymer composites was significantly higher than that of the reinforced cement composites. In addition, scanning electron microscopic images also showed that even at higher temperatures, the geopolymer matrix is present on the AMF fibre, which results in higher residual strength than the cement composites in which a negligible amount of matrix is present on the fibres.

Experimental study on the effect of age hardening and graphite particulate on the microstructure of aluminium metal matrix composites

The present paper investigates the effect of age hardening and the percentage of graphite particles on the microstructure of aluminium metal matrix composites fabricated by the stir casting method. The fabricated specimens were subjected to aging at a temperature of 170 °C and 270 °C for 2 h after the solution heat treatment and at a temperature of 500 °C for 1 h followed by water quenching. Both cast and aged specimens were characterized and its microstructure study revealed the distribution of graphite particles in molten aluminium metal, reaction at the bonded interface, and eutectic silicon from a course plate-like to fine branched at grain boundaries. The hardness, tensile and fatigue properties of composites were influenced by % graphite particles, thermal barrier coatings, and aging temperature. The fractured surfaces were analyzed using an electron microscope to understand the failure mechanism.

Analysis and prediction of tensile properties based on rule of mixtures model for multi-scale ramie plain woven fabric reinforced composite

Natural fibers are increasingly used as sustainable reinforcement for composites because of their carbon capture and renewability. Classical rule of mixtures (ROM) and ROM-based models have been widely used to predict the tensile properties of natural fiber reinforced composites with random or unidirectional oriented structures. However, the woven fabric reinforcement is interwoven by warp and weft yarns, which are spun by short fibers. The multi-scale composite structure made tensile properties challenging to predict. To provide the prediction of woven fabric reinforced composites, the macro and micro ramie fiber reinforced composites fabricated by multi-layer ramie plain woven fabrics, single-layer fabric, and detached yarn were analyzed. Results demonstrated that tensile properties of composites in the warp direction are lower than that in the weft direction due to yarn crimp and weaving damage. The linear fracture behavior of various composites confirms the hierarchical relationship between internal structure and tensile properties. The actual yarn volume fraction in fabrics or composites is calculated and introduced to the ROM model. The improved ROM model significantly enhances the prediction accuracy and efficiency of ramie plain woven fabric reinforced composites in five different areal densities and two interwoven directions.

The effect of stacking sequence and fiber orientation on tensile and flexural strength of fiber reinforced composite fabricated by VARTM process

In this study, Carbon, Glass, and Aramid fiber reinforced composite and their hybridized forms were fabricated using five different stacking sequences of the fabrics. Using the Vacuum Assisted Resin Transfer Molding (VARTM) procedure, epoxy resin was injected into these fabrics and allowed to cure at room temperature. From these five stacking sequences, a standard specimen with four different orientations viz. 0/90°, 15/75°, 30/60°, 45/-45° orientations were obtained using the Abrasive Water Jet Machining(AWJM) Process. The influence of stacking order and fiber orientation on tensile and flexural properties of composite was investigated. From the result of tensile testing, the highest and lowest tensile strength values were observed for neat carbon fiber reinforced composite at 0/90° orientation and at 45/-45° orientation respectively. The highest flexural strength was achieved in a hybrid combination of two layers of carbon, glass and aramid fabric for 0/90° whereas the lowest flexural strength was found in glass reinforced composite for the 45/-45° orientation.

Tensile Properties of Polypropylene Composites Reinforced with Alumina Nanoparticles and Short Carbon Fibers

Tensile Properties of Polypropylene Composites Reinforced with Alumina Nanoparticles and Short Carbon Fibers

Long-term stable and sustainable high-strength engineered cementitious composite incorporating limestone powder

High-strength engineered cementitious composite (HS-ECC) features low water-to-binder ratio and high-volume cement may result in time-dependent increase of matrix fracture toughness, loss of tensile ductility and high environmental impact. Inert limestone powder (LP) partially replacing cement can stabilize the long-term matrix fracture toughness of HS-ECC. In this study, the impacts of high-level replacement of cement with LP on the short- (28 d) and long-term (360 d) microstructure and mechanical properties of HS-ECC were investigated. Despite lower compressive strength, the tensile properties of HS-ECC with higher LP content were found to be more stable. The composite tensile properties can be traced to the fiber/matrix interface properties via a micromechanical model. The stability function of LP on the long-term tensile properties of HS-ECC was experimentally and theoretically verified. Further, the high-level replacement of cement with LP notably enhanced the sustainability of HS-ECC.

Lauric Acid Treatments to Oxidized and Control Biochars and Their Effects on Rubber Composite Tensile Properties

Biochar is a renewable source of carbon that can partially replace carbon black as filler in rubber composites. Since the carbon content of biochar is less pure than carbon black, improvements and modifications must be made to biochar to make it a viable co-filler. In this work, two methods to change the surface chemistry of biochar were employed: (1) gas treatment at 300 °C with either air or carbon dioxide, and (2) coating with lauric acid. Both methods are amenable to the current rubber processing industry. After biochar was treated with these methods, it was used as co-filler in rubber composite samples. Gas treatment with either air or carbon dioxide was found to increase stiffness in the final composites. Although lauric acid coating of biochar by itself did not have a significant effect on tensile properties, biochar that was first treated with carbon dioxide and then coated with lauric acid showed a 19% increase in tensile strength and a 48% increase in toughness. Gas treatment and lauric acid coating of biochar provide relatively simple processing techniques to improve the stiffness and tensile strength of biochar as rubber composite filler.

Fully biobased composite and fiber‐metal laminates reinforced with Cynodon spp. fibers

AbstractBiobased products promote efficient industrial use of natural resources, directly contributing to circular economy principles and sustainable development. This work investigates biocomposites made from Hay Tifton 85 grass fibers (i.e., Cynodon spp.) combined with castor oil polyurethane or epoxy matrices and their evaluation as core materials for novel fiber metal laminates (FMLs). A full factorial design is used to identify the effects of polymer type and fiber length on the tensile, flexural, compression and impact properties of composites. A cold pressing technique is used to manufacture random‐fiber composites and FMLs made of aluminum skins. The castor oil matrix shows promise for dynamic applications, while the epoxy matrix provides better performance under static loads. Composites achieved improved mechanical properties attributed to their lower porosity. The mechanical properties of FMLs under tensile flexural and impact (Charpy and drop tower) are also considerably higher than those of fiber‐reinforced polymers. Fully biobased laminates offer potential advantages compared to epoxy polymer composites. Their use as cores in FMLs can be extended to applications related to the automotive, civil construction and aeronautical sectors, fostering sustainable industrial designs.

Numerical simulation on mechanical properties and damage behavior of CFRP with self-healing microvascular channels

In this study, 3D representative volume element models with microchannels were established based on measured data. And the periodic boundary conditions were moderately modified to adapt to the actual constraints of the studied object. The effects of different microvascular parameters on the tensile and compressive properties of composites were studied. And the damage pattern of carbon fiber as the main load-bearing phase under the force was analyzed. The models were verified by tensile testing and micromorphology experiments. The research results are of application to the design and analysis of CFRP laminates containing similar microchannel structures.

Carbon nanotube to enhancing mechanical properties of three-dimensional woven modified-basalt fiber composites

3D woven composites offer various high-performance characteristics and wide applications due to their lightweight, high strength, and good integrity. However, to exploit their structural advantages, it is necessary to improve the interface properties between reinforcement and matrix, and carbon nanotubes with excellent mechanical properties provide a good solution to improve the interface properties of composites. Based on this motivation, the goal of this study is to investigate the impact of multiwalled carbon nanotubes on the tensile and bending properties of basalt fiber through-angle interlocking 3D woven composite, layered-angle interlocking 3D woven composite and orthogonal 3D woven composite. The obtained results indicated that the maximum warp and weft tensile loads of the layered-angle interlocking composites increased by 19.3% and 28.5% from 91,091.3N and 8,409.5N to 9,288.4N and 11,761.4N, respectively. The maximum warp and weft bending loads of 3D orthogonal composites were increased by 26.4% and 19.6% from 566.7N and 635.4N to 770.0N and 790.3N, respectively. O-MWCNTs contain -OH, -COOH and the unsaturated double bond can active functional groups and basalt fiber on the surface of the Si-OH and unsaturated double bonds in the reaction to form epoxy resin covalent bond to improve the interface between the fiber and matrix effect, which solved the key problem of interface outstanding performance of 3D woven modified-basalt fiber composites.

Cold nitrogen plasma treated glass fiber warp knitted structural composites: mechanical properties and response surface analysis

This study reveals the characterization and mechanical properties of glass fiber warp knit structural fabric/vinyl ester resin composites treated by cold nitrogen glow discharge plasma. The effects of nitrogen plasma treating parameters (including power, flow rate, and time) on tensile and bending properties of glass fiber warp knit structural composites were investigated. It was shown that nitrogen plasma treatment enhanced the tensile and bending property of the glass fiber warp knit structural composites. SEM, FTIR and AFM characterized etching existing on the surface, C-N and N-H groups were introduced, and varying degrees of roughness. The response surface analysis represented that the nitrogen plasma treated glass fiber warp knit structural composites obtained optimized bending properties with the power ranging from 130 W to 160 W, the flow rate ranging from 8sccm to 9sccm, and the time ranging from 100s to 110s.

Investigation of tensile and flexural properties of kenaf fiber-reinforced acrylonitrile butadiene styrene composites fabricated by fused deposition modeling

Employment of natural fiber for the filament of fused deposition modeling (FDM) can be found in numerous studies from different areas. However, the presence of fiber such as kenaf in polymer filament could cause mechanical properties degradation with regard to the fiber loading owing to low compatibility between natural fiber and polymer matrix. Therefore, this study aims to study the mechanical properties of three-dimensional (3D)-printed structures of composites specimens with varying volume percentages of kenaf fiber. From the tensile and flexural testings, the findings revealed decrements in the tensile strength and modulus of kenaf fiber-reinforced ABS (KRABS) composites from 0 to 5% contents of kenaf fiber which were 23.20 to 11.48 MPa and 328.17 to 184.48 MPa, respectively. The raising amount of kenaf fiber at 5 to 10% raised the tensile strength and modulus from 11.48 to 18.59 MPa and 184.48 to 275.58 MPa, respectively. Flexural strength and modulus of KRABS composites were decreased at to 5% from 40.56 to 26.48 MPa and 113.05 to 60 MPa, respectively. With further kenaf fiber addition from 5 to 10%, the flexural strength and modulus were increased from 26.48 to 32.64 MPa and 60 to 88.46 MPa, respectively. These results were supported by the finding from the morphological analysis, where the presence of porosity and fiber pull out implied the poor interfacial bonding between kenaf fiber and ABS matrix. This study has successfully demonstrated the tensile and flexural performances of different volume percentages of KRABS composites filament for FDM through experimental research.

Influencing Behavior Study of Natural Almond Shell Filler on the Tensile, Thermal, and Free Vibrational Properties of Flax Fiber Intertwined Vinyl Ester Composites

ABSTRACT The structural porosity weakness of a natural flax fiber-layered polymer laminate was reduced by the spatial rearrangement of natural almond shell filler occupying preferentially porous sites between the stacking layers, improving the properties of the polymer laminate. The present work investigates the mechanical, thermal, and free vibrational behavior of composites, including surface modification and the effect of almond shell filler loading in the flax fiber intertwined composites. Alkaline treatment of natural flax fiber and almond shell filler effectively reduced the hydrophilic contents of hemicellulose, lignin, and wax without altering the cellulose nature, as confirmed by FTIR analysis. Tensile strength was 35% higher for the alkaline-treated 10% almond shell-filled composite than the untreated filler composite. However, the tensile strength decreased beyond 10% of filler loading because of the poor dispersion of fillers in the matrix. As evident in the 10% filled almond shell composite, due to stronger interaction, polymer-mixed almond fillers act as a thermal insulating layer between the flax stacks, increasing thermal stability. Alkali treatment with an almond shell of 10 wt% filled flax fiber composite exhibited a higher natural frequency (185 Hz) and damping value (0.042) due to total internal dissipation of dynamic forces.

Effect of hybridization on crystallization behavior, mechanical properties, and toughening mechanisms in rubber-modified polypropylene flax fiber composites

Nowadays, the significance of sustainability has urged composite manufacturers to replace traditional synthetic fibers with eco-friendly natural alternatives due to their environmental and economic benefits. This work aims to fabricate hybrid polypropylene (PP) composites with short flax fibers, octene-ethylene copolymer (POE) rubber particles, and maleic anhydride-grafted polypropylene (MAPP) compatibilizer. The main goal is to gain an insight into the combined effect of toughening mechanisms induced by the short fibers and rubber particles at the crack tip and wake of composites, which is a crucial step in reaching a balance between toughness and rigidity. In this regard, a novel microscopy strategy is taken to elucidate the operating mechanisms at the crack tip and crack wake of composites. Also, differential scanning calorimetry (DSC), tensile, and Charpy impact tests were employed to investigate the effect of hybridization on the crystallization behavior, tensile, and impact properties of composites. The experimental results showed that the combined effect of encouraging matrix plastic deformation and synergistic work of toughening mechanisms at the crack tip and wake in the MAPP-modified hybrid composites containing 30% flax fibers and 10% POE rubber particles yielded an optimal improvement of 315%, 135%, and 37% in impact strength, elastic modulus, and ultimate tensile strength, respectively, over the neat PP formulation.

Tensile and microstructural properties of unidirectional coir bio-derived epoxy composites

The study investigates the possibilities of reinforcing bio-derived epoxy (bio-epoxy) polymer with unidirectional arrays of coir fibre using hand layup. The coir fibres were unidirectionally prepared in two layers. The tensile properties such as strength, Young’s modulus and elongation at break were found to be 43.83 MPa, 2.4 GPa and 2.72 % respectively. The tensile strength of coir/bio-epoxy composite was higher than the unreinforced bio-epoxy resin. The fibre volume fraction of the composites obtained using ImageJ on an 8-bit grey scale was 34%. The optical microstructure of the composites shows the distribution of the fibres within the bio-epoxy matrix.