Tensile Properties Of Composites Research Articles

Mechanical and tribological properties of silicon carbide /carbon fiber/epoxy resin based composites

In this contribution, an epoxy resin based composites which synergistically modified by carbon fiber (MCF) and silicon carbide (SiC) particles were prepared. The chemical structure of MCF and SiC before and after surface treated using silane coupling agent were analyzed by Fourier transform infrared spectroscopy and X-ray diffraction, respectively. The mechanical properties including tensile, flexural, and compression of the composites were investigated. Moreover, the friction and wear performances were studied on a ball-on-ring wear tester. The results indicated that the best tensile, compressive, and friction and wear properties of composites were obtained when SiC particles content is 3.0 wt.%. Compared to the pure epoxy resin, when the SiC particles content is 4.0 wt.%, the best flexural strength and modulus were obtained, which increased by 8.7% and 52.97%, respectively. Both the average coefficient of friction (COF) and the wear mass losses of the composites decreased significantly with the addition of the modified SiC particles. In addition, the main wear mechanism of pure EP is adhesive and fatigue wear, while the SiC/MCF/EP composites exhibit abrasive and fatigue wear.

Using polyethylene terephthalate bottle waste as a viable precursor for the synthesis of unsaturated polyester resin in fabrication of jute fibre reinforced composites

The present research effort employs glycolysed polyethylene terephthalate (PET) bottle waste as a precursor for the synthesis of unsaturated polyester resin (rUPR). This resin is then used for manufacturing composites that are reinforced with jute fibres using the sheet moulding compound technique. The limited crosslinking of styrene in the rUPR was elucidated using a combination of differential scanning calorimetry (DSC) and Fourier transform infrared spectroscopy (FTIR) analysis. The elevated exothermic reaction energy of 1152 kJ and the clearly identifiable peak observed at 1620 cm−1 in the Fourier Transform Infrared (FTIR) spectrum provided substantial evidence for this phenomenon. Additionally, the X-ray diffraction (XRD) analysis indicated that the recycled unsaturated polyester resin (rUPR) demonstrated a higher level of amorphous nature This observation can be attributed to reduced viscosity and enhanced ductility of rUPR. The utilisation of the rUPR as a matrix material has shown significant effectiveness in enhancing the tensile and flexural properties of composites reinforced with jute fibres. Thereby, the objective of this research is to develop a thermoset resin using recycled polyethylene terephthalate (rUPR) waste material for identification its suitability in manufacturing composites with jute fibres as reinforcement.

Study on the structure and thermal properties of graphite/copper laminated composites assembled by Ti-containing active filler metals

The development of high-power and small-sized electronic components requires the emergence of heat management materials with high heat flux. Hence, Ti-containing filler was used to braze graphite film/Cu high heat flux composites. The microstructure and forming mechanism of joints were studied, the influence of temperature on joint formation was analyzed, and the influence of graphite volume fraction on the thermal properties of the composites were discussed. The results show that the main microstructure of graphite/copper joints are Cu(s,s), Ti6Sn5 and CuTi2. As the brazing temperature increases, the carbide layer (TiC) that affects the connection gradually thickens, from <0.5 μm at 800 °C to 3 μm at 850 °C, which deeply improve heat transfer of composite materials. The tensile properties of composites also increase with increasing temperature, maximum tensile strength 31.94 MPa can be obtained at 850 °C. Furthermore, the composites are proved to possess high heat flux during process of heat transfer, and the transfer rate was 1.77 times that of Cu, 3.72 times of Al. The temperature rise test carry out in hot bench intuitively demonstrating that the composites have faster heating rate. Al used 197 s to raise from 25 °C to 50.5 °C, Cu used 140 s, while 76.92 % graphite-contained composites only took 75 s in the same volume and experimental condition.

Tensile properties of thermoset composites based on yarn structures from recycled carbon fibre and low melting temperature Co-polyamide fibre

The tensile properties of thermoplastic composites based on hybrid yarn structures consisting of recycled carbon fibre (rCF) and thermoplastic fibres (rCF content of the hybrid yarn approx. 50–60% by weight) have been reported previously. To date, no report has been found on the tensile properties of thermoset composites based on yarns with high rCF content (&gt;90% by weight). The reasons for this are the complex mechanisms involved in processing pure rCF due to the low shear strength, smooth fibre surface, small fibre diameter and high brittleness of rCF. Yarns made of rCF (≥90% weight) for thermoset composites have been developed in a fundamental research project at the ITM. This paper reports on the tensile properties of unidirectional composites based on yarns composed of staple rCF (&gt;90%) and low melting co-polyamide fibres produced by varying spinning parameters. Furthermore, in order to increase the infiltration of the epoxy matrix during the composite manufacturing process, the yarns are thermally treated at 180°C prior to infiltration and its effect on the tensile properties of the composites is analysed. The results show that the thermal treatment of the yarn prior to infiltration with the matrix, compared to the yarn without prior thermal treatment, helps to achieve better impregnation and therefore better tensile strength of the composites compared to the yarn without prior thermal treatment. A Youngs’ modulus and tensile strength of 86 ± 11 GPa and 1181 ± 71 MPa respectively are achieved in thermoset composites based on the developed yarns.

Tensile Properties of Aluminum Matrix Composites Produced via a Nitrogen-Induced Self-Forming Process

This study compares the tensile properties of commercial aluminum matrix composites (AMCs) with those of AMCs produced via a nitrogen-induced self-forming process. This process is a newly developed AMCs manufacturing process that takes advantage of the price competitiveness and productivity of large-scale products produced via the liquid process. Additionally, this process has the freedom of choice of the reinforcement phase and the homogeneous dispersibility of the powder process. Compared to commercial monolithic 6061 alloys, 6061 aluminum alloy matrix composites exhibit increased Young’s modulus, yield strength, and ultimate tensile strength by 59%, 66%, and 81%, respectively. This study also compares the tensile properties of AMCs with different matrix compositions, including 2009 and 7050 aluminum alloys. The study shows that AMCs produced using the nitride-induced self-forming aluminum composite (NISFAC) process exhibit comparable or superior tensile properties to those obtained using existing commercial powder metallurgy (P/M) processes.

Bimodulus constitutive models and the simulation on bending properties of woven carbon fibre-reinforced composites

The tensile and compressive properties of woven carbon fibre-reinforced composites (CFRP) are different owing to the buckling and entanglement of fibre bundles. Two bimodulus constitutive models (TBM and PBM) were proposed based on the track stress criterion and principal stress criterion. Combined with the Hashin three-dimensional strength criterion and Alvaro stiffness reduction criterion, a material subroutine was written to calculate the bimodulus constitutive models. Three-point bending tests of [0/90]20 and [±45]20 were designed to obtain the load–displacement curves and failure modes. The precision of the calculation results with the traditional unimodulus model and bimodulus models were compared, and the bending performance of woven CFRP was explored. The results demonstrate that fibre fracture and interlayer damage occur with different stacking sequences. The material properties can be better shown with less error as bimodulus models. The stiffness and strength of the PBM were slightly larger than those of the TBM, and the failure factors were smaller than those of the TBM. The results of the TBM are closer to the test, and the material subroutine is easier to realise. Bimodulus constitutive models have good application prospect in woven composites for higher accuracy.

Effect of weight of Nanoclay on Tensile, Flexure and Toughness properties of Glass Epoxy composites

In recent times, polymer composites have played an epochal role in transforming material science. Some of their properties such as toughness, strength, flexibility, and rigidity have helped them supplant conventional materials such as iron, steel, and aluminium on several occasions. Apart from this, they are light in weight and more cost-efficient, which make them a viable alternative. They have found their application in several fields such as automobile industry, aerospace industry, construction, and pipeline industry. The present investigation uses composite material fabricated with varying weight percentages of Nano clay viz 1.5, 3.5, and 5 which are compared with Neat Glass Epoxy composite. The reinforcement material used is Glass fibre. Three different orientations viz unidirectional, Symmetric and Asymmetric of the laminate are considered. The fabricated composite is characterized for various mechanical properties like tensile test, flexure, and Fracture toughness testing as per ASTM standards. The addition of Nano Clay showed the improvement in the Tensile, Flexure and Fracture Toughness of the for 3.5 wt% of Nanoclay. The properties under tensile loading i.e. the tensile strength is increased by 12% for Unidirectional laminate, flexure strength increased by 20% for Unidirectional laminate and 20% for Unidirectional laminate fracture Toughness.after 3.5 wt%, there seemed to be a decline in both the properties. The morphological assessment was done by scanning electron microscopy (SEM) where the microstructure was analyzed. The SEM images were used to study the activity of the Nanoclay within the fabricated composite. The overall test results suggested that the fiber reinforced nanoclay composites can fit for industrial applications like condenser blades and turbine blades.

Effects of polypropylene and basalt fibers on tensile and compressive mechanical properties of fiber-reinforced ice composites

As an environmentally friendly and low-cost construction material, ice has a rich historical usage and has been gaining significance in cold-zone engineering constructions. However, the low tensile strength and brittle damage characteristics limit the potential applications of ice. Incorporating fibers in ice has been recognized as an effective method to improve the mechanical properties. This research aims to investigate the effects of polypropylene fibers (PF) and basalt fibers (BF) on the mechanical properties of fiber-reinforced ice composites. To do so, approximately 200 PF- and/or BF-reinforced ice specimens with varying fiber contents (0 %, 2 %, 4 %, 6 %, 8 %) were produced and subjected to splitting tensile and uniaxial compressive tests at −10 °C. Besides, the synergistic effect of hybrid fiber-reinforced ice on tensile mechanical properties was further investigated. The experimental results demonstrate that the addition of fibers transforms the brittle failure of ice into ductile failure, and both BF and PF improve the tensile and compressive mechanical properties of ice composites in strength and ductility as functions of fiber contents. The tensile mechanical properties of hybrid fiber-reinforced ice exhibit both negative and positive synergistic effects. Furthermore, the research established the tensile and compressive strength formulas of PF- or BF-reinforced ice composites with different fiber contents, and the calculated results correlated well with the tested ones.

The flexible stab‐resistant composite membrane made by thermoplastic polyurethane filled with modified nanoparticles

AbstractThermoplastic polyurethane (TPU) has good elasticity and tear resistance, and is often applied in the field of flexible puncture resistance although the puncture resistance of pure TPU is limited. In this paper, silica powder (SiO2) and styrene butadiene rubber powder (SBR) with different concentrations were used as fillers to reinforce the TPU matrix respectively. To overcome the problem of poor interfacial compatibility between filler and matrix, the silane coupling agent r‐Aminopropyltrieth oxysilanee (KH550) was selected to modify the particles. The compatibility of particles and matrix, the puncture properties and tensile properties of composites were assessed by FTIR, TEM, SEM, tensile testing, and needle puncture testing. Further, the tensile and puncture properties of composites with different types and concentrations of particles were systematically compared and analyzed to find optimal parameters. The results show that the best modification effect is gained when the mass ratio of KH550 and nanoparticles is 0.85:1 and the specific puncture strength of TPU membranes incorporated modified SiO2 or SBR nanoparticles can be increased by up to 106.4% and 85% respectively compared to pure TPU membrane.

The Influence of Heat Treatment Temperature on Tensile Properties of Metal-Bonded Diamond Composites Fabricated via Selective Laser Melting.

Selective Laser Melting (SLM) is an effective technology for fabricating new types of porous metal-bonded diamond tools with complex geometries. However, due to the high cooling rate and internal stresses during SLM fabrication, defects such as high porosities and interface gaps still need to be resolved before it can be considered for use in other applications. The influence of heat treatment temperature on internal characterization, interface microstructures, and tensile properties of AlSi7Mg-bonded diamond composites fabricated by SLM were investigated in this work. From experimental results, the porosities of HT-200, HT-350, and HT-500 specimens were 12.19%, 11.37%, and 11.14%, respectively, showing a slightly lower percentage than that of the No-HT specimen (13.34%). Here, HT represents "Heat Treatment". For No-HT specimens, an obvious un-bonding area can be seen in the interface between AlSi7Mg and diamond, whereas a relative closer interface can be observed for HT-500 specimens. After heat treatment, the elastic modulus of specimens showed a relative stable value (16.77 ± 2.79~18.23 ± 1.72 GPa), while the value of yield strength decreased from 97.24 ± 4.48 to 44.94 ± 7.06 MPa and the value of elongation increased from 1.98 ± 0.05 to 6.62 ± 0.51%. This difference can be attributed mainly to the disappearance of the solid-solution hardening effect due to the increase of Si content after heat treatment.

Utilization of Torrefied and Non-Torrefied Short Rotation Willow in Wood-Plastic Composites.

The torrefaction process is widely used in the energy field, but the characteristics of the torrefied wood also have positive effects on the production of wood plastic composites. In this study, short-rotation shrub willow was torrefied at 225 and 300 °C and incorporated into polypropylene composites filled with changing levels of weight percent (wt%) of non-torrefied and torrefied (5, 15, 25, and 40 wt%) wood. Nine different formulations were extruded for mechanical, thermal, and water absorption properties. The tensile properties of composites were not affected by any level of torrefaction, while higher flexure properties were in favor of lower wt% of torrefied wood. The slowest rate of thermal degradation was confirmed for the highest wt% of torrefied wood with a torrefaction temperature of 300 °C. In contrast, the presence of torrefied wood in composites did not show a difference in crystallization or melting temperatures. The most noticeable contribution of torrefaction temperature and wt% was found for water-absorbing properties, where the higher torrefaction temperature and largest wt% of torrefied wood in the composite resulted in decreased water uptake.

Influence of moisture absorption on tensile and compressive properties of natural fiber-reinforced thermoplastic composites

ABSTRACT The present research is aimed at examining the changes in tensile and compressive properties of natural fiber-reinforced composites (NFRC) exposed to various humidity conditions; this is due to the fact that moisture content (MC) in fibers is generally assumed to be detrimental to composite performance. It was found that once moisture is exposed, compressive strength and strain of specimens would be higher than those of tensile, whereas modulus of elasticity would be lower. Due to increasing moisture content, although elongation in all tests was enhanced, tensile and compressive strength declined by 15% and modulus of elasticity decreased by 20%. In addition, Poisson’s ratio for both compressive and tensile properties was nearly identical (0.33) in distinct moisture content. A new understanding of moisture’s effects on mechanical behavior is presented in this study by finding an optimum point for exposing moisture to increase compressive and tensile strength.

A UNIFIED MACHINE LEARNING MODEL TO PREDICT ULTIMATE TENSILE AND BOND CAPACITY OF FRCM

Fiber-reinforced cementitious matrix (FRCM) is a new-era material for strengthening concrete and masonry structures. Unlike Fiber reinforced polymer (FRP), it has excellent substrate bond properties. However, FRCM shows intra-fiber slip and Fiber-matrix debonding as its major failure modes, effectively reducing its ultimate load-carrying capacity. It has led to broad research scope, and researchers have used permutations and combinations of various types of fibers, matrices, coatings, and substrates to improve the tensile and bond properties of the FRCM composites. Additionally, other experimental parameters, such as rate of loading and experimental setup (clevis, hydraulic or mechanical), affect the tensile and bond properties of FRCM composites. Complex failure modes and parameters make tensile and bond capacity prediction very difficult. Previous attempts by researchers showed the effectiveness of machine learning in predicting the bond capacity of the FRCM composites. Artificial neural network (ANN) based models have also been used successfully to predict the flexural capacity of FRCM-strengthened masonry panels. This study develops a unified machine learning-based model to predict bond and tensile capacity using complex tree-based algorithms such as extra tree regressor, categorically boosted trees, extreme Gradient boosted trees, etc. The authors extracted 603 data points from the literature to develop and validate the model; this includes 345 data points from tensile testing and 258 data points from FRCM-concrete bond testing. It is found that the developed tree-based model predicts the ultimate tensile and bond capacity with about 93% and 95% overall accuracy, respectively.

A UNIFIED MACHINE LEARNING MODEL TO PREDICT ULTIMATE TENSILE AND BOND CAPACITY OF FRCM

Fiber-reinforced cementitious matrix (FRCM) is a new-era material for strengthening concrete and masonry structures. Unlike Fiber reinforced polymer (FRP), it has excellent substrate bond properties. However, FRCM shows intra-fiber slip and Fiber-matrix debonding as its major failure modes, effectively reducing its ultimate load-carrying capacity. It has led to broad research scope, and researchers have used permutations and combinations of various types of fibers, matrices, coatings, and substrates to improve the tensile and bond properties of the FRCM composites. Additionally, other experimental parameters, such as rate of loading and experimental setup (clevis, hydraulic or mechanical), affect the tensile and bond properties of FRCM composites. Complex failure modes and parameters make tensile and bond capacity prediction very difficult. Previous attempts by researchers showed the effectiveness of machine learning in predicting the bond capacity of the FRCM composites. Artificial neural network (ANN) based models have also been used successfully to predict the flexural capacity of FRCM-strengthened masonry panels. This study develops a unified machine learning-based model to predict bond and tensile capacity using complex tree-based algorithms such as extra tree regressor, categorically boosted trees, extreme Gradient boosted trees, etc. The authors extracted 603 data points from the literature to develop and validate the model; this includes 345 data points from tensile testing and 258 data points from FRCM-concrete bond testing. It is found that the developed tree-based model predicts the ultimate tensile and bond capacity with about 93% and 95% overall accuracy, respectively.

Effect of Strain Rate and Temperature on the Tensile Properties of Long Glass Fiber-Reinforced Polypropylene Composites.

Strain rate and temperature are influential factors that significantly impact the mechanical properties of long glass fiber-reinforced polypropylene composites. This study aims to investigate the tensile properties of these composites, analyzing the effects of temperature, strain rate, and their interplay on variables such as tensile stress, tensile strength, fracture stress, and fracture morphology through a series of comprehensive tensile experiments. The experimental results demonstrate a notable increase in both tensile strength and tensile fracture stress when the temperature is set at 25 °C, accompanied by strain rates of 10-4, 10-3, 10-2, and 10-1 s-1. Conversely, a significant decrease is observed in the aforementioned properties when the strain rate is fixed at 10-4, while varying temperatures of -25 °C, 0 °C, 25 °C, 50 °C, and 75 °C are applied. At lower temperatures, cracks manifest on the fracture surface, while matrix softening occurs at higher temperatures. Additionally, in the context of strain rate-temperature coupling, the decreasing trend of both tensile strength and tensile fracture stress decelerates as the temperature ranges from -25 °C to 75 °C at a strain rate of 10-1, compared to 10-4 s-1. These findings highlight the significant influence of both strain rate and temperature on high fiber content long glass fiber-reinforced polypropylene composites.

Investigation on mechanical properties of novel natural fiber-epoxy resin hybrid composites for engineering structural applications

Polymers and fibers are the main components of cementitious composite materials to reinforce concrete. The synthetic fibers used in concrete composites typically weigh and also, and they are easily subjected to thermal degradation. To tackle the above issues, researchers developed various natural fiber-based composites. In the paper, the mechanical characteristics of hybrid composites were examined. The hybrid composites were developed using Madar, Gongura, and Hibiscus cannabinus fibers. The polyester resin was the matrix. The fibers were treated chemically using a 5% sodium hydroxide (NaOH) solution. The fibers were then carefully cleaned with distilled water twice and baked for 70 min at 60 °C. For the evaluation of the tensile, flexural, and impact properties of the hybrid composites, specimens were made in accordance with ASTM standards. The treated composite sample (S3) specimen exhibits a tensile strength (TS) of approximately 34.720 N/mm2, flexural strength (FS) of 77.957 MPa, and flexural modulus (FM) of 1548.588 GPa. The average water absorption of the sample is only 2.45%. The hardness and impact strength (IS) of the samples are also superior to those of several other composites studied in the literature. Hence, the proposed hybrid composites could be a potential material for reinforcing the concrete composites to provide a higher service rate and greater durability to the structures.

Effect of Self-Healing by Dicyclopentadiene Microcapsules on Tensile and Fatigue Properties of Epoxy Composites.

Microcapsules of urea-formaldehyde (UF) containing dicyclopentadiene (DCPD) were synthesized by the in situ polymerization technique for self-healing of epoxy. The dispersion of microcapsules in the epoxy matrix was achieved using ultrasonication. Composites of epoxy, having 0.5, 1.0, 1.5, and 2.0 wt.% of microcapsules capable of self-healing, were prepared. The shape and size of the microcapsules were determined by field emission electron microscopy. Spherical capsules of DCPD, with an average diameter of 172 nm, were obtained. Investigation of tensile properties indicated a decrease in the tensile modulus with an increase in wt.% of microcapsules. There was a reduction of 22%, 27%, 39%, and 30% in the elastic modulus of composites for 0.5, 1.0, 1.5, and 2.0 wt.% of microcapsules, respectively. Tensile strength was found to increase with an increase in wt.% of microcapsules. The tensile strength of the composites increased by 33%, 20%, 8%, and 21% for 0.5, 1.0, 1.5, and 2.0 wt.% of microcapsules, respectively, in comparison with that of neat epoxy. The fatigue life of composites was investigated by conducting uniaxial tension-tension fatigue tests at constant stress amplitudes of 20, 25, 30, and 35 MPa, at a constant stress ratio (R = 0.1) and a frequency of 3 Hz. The fatigue life of composites increased with an increase in wt.% of microcapsules in comparison with that of neat epoxy. It was found that the fatigue life of the composites decreased with 1.5 and 2.0 wt.% of microcapsules in comparison with composites with 0.5 and 1.0 wt.% of microcapsules. The fracture surfaces of the tested samples were examined with the help of scanning electron microscopy (SEM) to understand the various mechanisms responsible for the change in modulus, strength, failure strain, and fatigue life of composites.

An experimental investigation of the tensile, fracture and microstructural characteristics of ABS/SBS reinforced with HNTs

AbstractThermoplastic composites are broadly used in many industries. Excellent mechanical characteristics are frequently required to achieve the appropriate properties for the applications. Therefore, the objectives of this study were (1) presenting an in‐depth analysis of the effects of styrene butadiene styrene (SBS) and halloysite nanotubes (HNTs) on the tensile and fracture properties of the thermoplastic composites based on acrylonitrile butadiene styrene (ABS), and (2) examining the relationship between the microstructure of the thermoplastic composites and their mechanical behavior. For these purposes, HNTs were utilized with four levels (0, 1, 3, and 5 wt%) and SBS was used with two levels (15 and 30 wt%). The tensile strength and modulus were reduced by adding SBS to 30 wt%; however, the elongation at break was increased by 30%. Furthermore, tensile strength and modulus, and elongation at break were improved by increasing HNTs up to 3 wt%. The results indicated the elastic work (we) and plastic work (βwp) rose by 29% and 10%, respectively, when 30 wt% of SBS was added to ABS. Furthermore, we and βwp rose by the addition of HNTs up to 3 wt%. To examine fracture mechanisms, field emission scanning electron microscope (FESEM) images of the fracture surface of the essential work of fracture (EWF) specimens were taken. Several voids are present in the compounds containing SBS, activating the plastic deformation mechanism. Based on the optimization process, the best strength, stiffness, and toughness balance was attained for the compound consisting of 15 wt% SBS and 1 wt% HNTs.Highlights The effects of HNTs and SBS on the fracture properties of polymer composites. The addition of SBS increased we, βwp, and the elongation at break. HNTs had a positive effect on the tensile strength and modulus, we, and βwp. The important mechanisms include plastic deformation and cavitation.

Influence of Mechanical Properties on the Characteristics of Jute/Kevlar-based Epoxy Hybrid Composites

The earth has an infinite number of fibres. Now-a-days renewable fibre is being used as an alternative to traditional petroleum-based components. In this paper, we use an experimental method to evaluate the influence of the golden fibre (jute) with para-aramid (kevlar) to create a specialized composite material. The tensile and flexural properties of jute-kevlar matrix composites are determined layer by layer to increase the composite quality and acquire the desired properties. The jute and kevlar fibre are mixed in equal proportion as this prospectus, they are layered and finally strengthened by epoxy and their hybrid composites characteristics are analysed.

Effect of Curing Process on Tensile and Flexural Properties of 3D Woven Structural Polymer Composites

Effect of Curing Process on Tensile and Flexural Properties of 3D Woven Structural Polymer Composites