Tensile Strength Of Composite Materials Research Articles

Influence of Recycled Aggregates and Silica fumes on Compression and Split Tensile Strength of Composite Materials

Influence of Recycled Aggregates and Silica fumes on Compression and Split Tensile Strength of Composite Materials

Tree-based machine learning approach to modelling tensile strength retention of Fibre Reinforced Polymer composites exposed to elevated temperatures

Fibre Reinforced Polymer (FRP) composites are susceptible to degradation at elevated temperatures. Accurate modelling of the tensile performance of FRP composites under high-temperature exposure is crucial for their structural integrity. In this study, tree-based models, namely, decision tree, M5P, and random forest methods, are utilised to model the impact of elevated temperatures on the tensile strength of composite materials. A database of 787 experimental results is established and processed to train and test the regression tree models. The exposure temperature, resin glass transition temperature, sample thickness/diameter, exposure duration, ambient cooling, fibre-to-resin ratio, fibre orientation, resin type, fibre type, and manufacturing process were considered as the main parameters affecting the tensile strength retention (TSR) of FRP composites after exposure to elevated temperatures. To improve the prediction performance of machine learning, Bayesian optimisation and 10-fold cross validation (CV) technique were used to train regression tree methods. The results demonstrated the accuracy of the developed models in predicting the TSR of the composites under elevated temperatures. Feature contribution analysis showed that the exposure temperature exerts the most significant impact on the TSR, with the glass transition temperature coming next in importance. These were followed by sample thickness, exposure duration, ambient cooling, fibre-to-resin ratio, and fibre orientation, respectively. Resin type, fibre type, and the manufacturing process had the least contributions to the observed variations in TSR. Examining the tensile strength retention of FRP composites at high temperatures enables the development of precise predictive models and design guidelines for their optimal use across industries.

Exploding wire method for the characterization of dynamic tensile strength of composite materials

In the presented study a wire electric explosion method is adopted for the shock loading test of wound T700/LY113 carbon/epoxy composite. The advantage of the proposed test method is a possibility to reach strain rate ∼104 s−1, exceeding upper limit of split Hopkinson pressure bar, but matching lower limits of plate impact test. Compared to the latter test method, a promising feature is a capability to measure in-plane tensile strength of the laminated composite. To implement the proposed method, test samples were fabricated by winding of carbon fiber layers over a polymethyl methacrylate (PMMA) cylinder. Electric explosion of wire inserted in the channel inside the cylinder generates a shock wave, which propagates towards the outer composite shell, and free surface velocity history is recorded using a laser interferometer. It allows estimation of failure strain and tensile strength of the composite in circumferential direction. However, incident shock wave and reverberations are also critical for out-of-plane strength, including delamination, so finite element analysis is used to elaborate what type of failure mode is critical.

Studying the influence of technological factors on properties of protective composite materials based on Kevlar fabric and

Bullet-resistance and weight are important features of anti ballistic materials. Kevlar fibers are the widest reinforcement material for military and civil systems due to their excellent impact resistance and high strength-to-weight ratio. Kevlar fibre based composites are used for designing personal helmets and body armor to effectively stop both fragmentation and bullets. In this report, the influences of fabrics and technological factors on the properties of the composite made of kevlar and PVB/PF resin were studied. The results showed the composite sample with desired properties could be achieved by using the Kevlar fabric K-129 with the weight ratio of fabric:resin = 0.8:0.2 under the processing conditions: temperature-150 oC, pressing pressure-150 kg/cm2, pressing period-45 minutes. The tensile strength of composite materials is 743.52 Mpa. The composite samples in the shape of plate and helmet passed the ballistic tests with 17 grains (1.1 grams) of Fragment Simulating Projectiles (FSPs) at a speed of 438.92 m/s.

Research on Preparation and Mechanical Properties of Multilayer Graphene Reinforced Aluminum Matrix Composite

In order to solve the problem of the dispersion of graphene in aluminum-based composite materials, a high-energy ball milling method was used to prepare graphene/aluminum-based composite powder, and then the graphene/aluminum composite material was obtained by vacuum hot pressing. XRD, SEM, TEM were used to analyze and study the morphology and microstructure of graphene/aluminum-based composite powders, and the tensile mechanical properties, hardness and fracture morphology characteristics of graphene/aluminum-based composites. The research results show that the addition of graphene can reduce the cold welding of aluminum powder during the high-energy ball milling process, and obtain better dispersed graphene/aluminum composite powder; when the content of graphene is 1 wt.%, the composite material The tensile strength can reach 295.62 MPa, the hardness is 113.6HV, which is 24% higher than the pure aluminum tensile strength, and the hardness is increased by 20%; graphene exists in the dimples of the tensile fracture, under the action of tensile force, Graphene can carry load transfer and improve the tensile strength of composite materials, which is the enhancement mechanism of graphene in aluminum-based composite materials.

Rotational molding of polylactide (PLA) composites filled with copper slag as a waste filler from metallurgical industry

The research work carried out so far indicates the ever wider possibilities and demand for shaping composite products in the rotational molding technology. This trend was the main reason to use waste-based filler from the metallurgical process as a filler for manufacturing polylactide (PLA)-based remolded composites. Copper slag (CS) was introduced in the single-step processing method to PLA matrix at 5, 10, 20, and 35 wt%. The rotomolded composites with different filler content were subjected to in-depth structural analysis discussed in relationship with mechanical and thermomechanical properties changes. Evaluation of the composite structures by scanning electron microscopy (SEM) and 3D computed tomography (3D CT) analyses showed that incorporating up to 10 wt% of the filler did not cause adverse changes in the filler dispersion in the product volume, which was homogeneous. Lack of unfavorable structural changes in composites with concentrations of up to 20 wt% was related to the rheological properties of the composition. Except for series with the highest filler content (35 wt%), the produced composites were characterized by increased stiffness and hardness than rotomolded parts made from pure PLA. Despite the deterioration of the tensile strength of composite materials using higher filler concentrations, the mechanical performance of 5 and 10 wt% showed an acceptable level while increasing the stiffness by about 15% compared to neat PLA. Moreover, it was shown that the interfacial adhesion between PLA and CS, despite the lack of surface modification of the filler waste, was advantageous.

Analysis of Tensile Strength of Citronella (Cymbopogon Nardus) Fiber Reinforced Composite Materials

The use of synthetic fibers in composite materials has a negative impact on the environment. One way to reduce this impact is to replace synthetic fibers with natural fibers. A natural fiber that has the potential as a mixed material in the manufacture of composite materials is citronella (Cymbopogon nardus) fiber. This study aims to determine the effect of volume fractions 40%, 50%, 60%, and 70% of citronella fiber with polyester resin matrix BQTN 157 on tensile strength. The process of making composites used the hand lay-up method. The specimen was formed according to the ASTM D3039 standard and the tensile strength of the specimen was tested by using a Universal Testing Machine (UTM). From the results of the study, the maximum tensile strength was found in the fiber volume fraction 70% of 77.35 MPa, the strain is 6.57%, and the modulus of elasticity is 1.177 GPa. This study indicates that fiber volume fraction affects the tensile strength of composite materials. Hence, the manufacture of composite materials which have good strength is influenced by many things such as raw materials, matrices, mixture composition, and methods.

Strength of carbon fiber/epoxy in sea water

Abstract Composite materials are widely used in the marine industry. The marine environment, on the other hand, has a significant impact on the strength of composite materials. The tensile strength is adversely affected because the matrix material absorbs water. In this study, the effect of orientation, number of layers and different mediums over time on the tensile strength of the woven carbon fiber reinforced epoxy composite material was investigated experimentally from a comprehensive perspective. The findings of the experiments were subjected to variance analysis. The repeated tests and cross-results of the experimental parameters were found to be compatible with each other. Seawater reduces the tensile strength of composite materials in any case. The tensile strength increased with increasing the number of layers. However, it has been observed that the seawater medium reduces strength when the number of layers increases. At the same time, as orientation angle rises, the seawater medium’s negative effect on strength rises.

Mechanical characterization of arhar biomass based porous nano activated carbon polymer composites

AbstractActivated carbon material was synthesized by two stage pyrolysis and chemical activation method using arhar fiber biomass as precursor. The effect of activation temperature on the characteristics of activated carbon materials was explored. Temperatures of 700°C, 800°C, and 900°C were used for the production of activated carbon materials. BET surface area, pore size, and pore volume were studied using N2 adsorption analysis. Activated carbon prepared at 800°C temperature was found to be effective; exhibited 504.6 m2/g surface area and pore volume of 0.245569 cm3/g with micropores of less than 20 Å diameter. XRD analysis of the material exhibited broad and sharp peaks in the range of 18 to 30 (2θ), confirming amorphous structure. From thermogravimetric analysis, it was noticed that activated carbon has high thermal stability. It was left with 62% of residual mass when subjected to 1400°C temperature. Activated carbon material synthesized at 800°C was used as filler while epoxy functioned as matrix material for fabrication of composites. The effect of filler loading on the tensile strength of composites was studied. Tensile strength of composite material increased with addition of filler loading. It was observed that composite with 2% filler loading had a maximum tensile strength of 56 MPa.

Robust, stretchable and photothermal self-healing polyurethane elastomer based on furan-modified polydopamine nanoparticles

The realization of high strengthen, large ductility, and multiple-responding for self-healing composites is an urgent problem to be solved for expanding practical applications in industry. Herein, a simple stagey was proposed to prepare multiple-responding self-healing composites, which possess outstanding both tensile strengths also ductility, by utilizing furfuryl-modified polydopamine particles (F-PDAPs) as crosslinkers in maleimide-terminated polyurethane (m-PU) based on Diels-Alder reaction. Due to the excellent photo-thermal effect of F-PDAPs and the existence of DA bonds, the composites exhibited excellent healing efficiency under NIR (91.83%) and thermal (92.54%) initiation, in particular, could locally and specifically repair any crack under near-infrared light conditions. Furthermore, the tensile strength of composite materials was reached up to 34.26 MPa with a high breaking strain of 800%. Besides, the composites exhibited outstanding adhesive strength that could be healed via thermally induced. Such excellent comprehensive performance gives the composite materials an opportunity to have great potential in the fields of coatings, binders, etc.

Preparation of PBS and CaCO3 Composite Degradable Materials based on Melt Blending

Poly (butylene succinate)(PBS)/Calcium carbonate (CaCO3) composite were prepared by melt blending, and studied the effect of different coupling agents, PBS and CaCO3 mass ratio and coupling agent for composite. The results showed that aluminum acid coupling agent for the properties of composite materials improved the most obviously effect; with CaCO3 content increased, the degradation properties and tensile strength of composite materials rose, the impact strength and elongation at break decreased. With aluminum acid content increased, the tensile propeties and impact strength increased and then stabilization but no influence on degradation. When the PBS and CaCO3 mass ratio was 7:3, the coupling agent in an amount of 1.5%, the performance of PBS/CaCO3composite was better, meeting the basic requirements. Compared with pure PBS, it reduced the cost of nearly 30%, and application further.

Parameters optimization of bio composite manufacturing using experimental design

Indonesia is one of the banana producing countries that reaches millions of tons every year. With a huge number of banana production, the waste from banana trees, especially banana midribs, is also enormous. Banana midribs or pseudo-stem is known to have robust tensile strength and can be made miscellaneous products, such as composite materials. Composites are currently used in industry many times, especially in the construction industry as partitioning and ceiling material. The purpose of this study was to discover the optimal parameters in the manufacture of bio composite materials in an effort to utilize the pseudo-stem and environmental sustainability. This study began with conducting experiments, testing the tensile strength of composite materials, and calculating the experimental results. The method applied was the factorial experimental design to figure out the best parameters in the manufacture of composite materials. The results showed that from the 3 factors used, the fiber direction had the substantial contribution, followed by the pressing duration and the adhesive type. Meanwhile, the combination of factors and levels that produced the optimum parameters for tensile strength were by using the adhesive type on level 1, the fiber direction on level 1, and the pressing duration on level 2 which are polyvinyl acetate (PVAc), unidirectional, and 1 hour, respectively.

Tensile test analysis of carbon fiber composite material by molecular dynamics simulation

In this study, the authors investigate the tensile strength at a carbon fiber/epoxy resin interface using molecular dynamics (MD) simulations. The simulated tension speed and strength were initially estimated, and a realistic tension speed was subsequently selected. The tensile strength calculated using the simulations was in good agreement with the experimental data. Based on the present study and our previous work, the factors contributing to the tensile strength of composite materials were investigated and analyzed. The surface energy between the graphene sheet and resin as well as the molecular structure of the resin in the vicinity of graphene was shown to significantly affect the tensile strength. In addition, the applicability of MD simulation as a useful tool for the prediction and analysis of composite materials was demonstrated. This work used graphene sheets as carbon fiber because it is difficult to express the real carbon fiber for simulation model.

PERBANDINGAN NILAI KEKUATAN TARIK KOMPOSIT MENGGUNAKAN METODE HAND LAY UP DAN METODE VARI

Some Types of the method of making composite materials are the Vacuum Assited Resin Infusion (VARI) Method and the Hand Lay Up Method. The purpose of this study was to compare the tensile strength of composite materials made using the hand lay up and VARI methods. The types of fibers used as composite materials are palm frond fibers and matrices used in polyester resin. Composites reinforced with palm fronds are printed using the hand lay up and VARI methods. The results showed the value of composite tensile strength with the hand lay up method of 27.37 MPa and composite tensile strength using the VARI method of 28.40 MPa. From the results of the study, the differences in the tensile strength values of the two methods were obtained.

Improvement of the Interfacial Adhesion Between Fiber and Matrix

Abstract In this work, the influence of carbon fiber surface treatment on mechanical properties of unsaturated polyester was investigated. Two approaches have been used in the surface treatment; the first is the desizing of the carbon fiber by the release of the epoxy layer. The second is with the release of epoxy layer and etching the fibers. It was concluded that both methods give good results on adhesion between the matrix and the fibers. It is found that the treatment of carbon fibers is efficient and greatly improves the CFRP handress. The tensile strength of composite materials increases by 30% for etched carbon fibers compared to untreated carbon fibers.SEM images confirm the results obtained.

Thermal conductivity of PVDF/PANI-nanofiber composite membrane aligned in an electric field

Poly(vinylidene fluoride) (PVDF) is a semi-crystalline thermoplastic polymer with excellent thermal stability, electrochemical stability and corrosion resistance, which has been widely studied and applied in industrial nonmetallic heat exchanger and piezoelectric-film sensor. In this study, polyaniline (PANI) nanofibers were synthesized using dodecylbenzene sulfonic acid as the surfactant. The obtained PANI nanofibers were blended in PVDF matrix to enhance thermal conductivity and tensile strength of composite materials. Electric field was applied for the orientation of membrane structure during membrane formation. Scanning electron microscope (SEM) images exhibited that the PANI nanofibers were well-dispersed in the composite membranes. The structure of composite membranes was more orderly after alignment. X-ray diffraction (XRD) and differential scanning calorimetry (DSC) indicated that the content of PANI nanofibers contributed to the transformation of PVDF from α-phase to β-phase. Both the tensile strength and thermal conductivity of composite membranes were significantly improved. This tendency was further enhanced by the application of electric field. The maximum tensile strength was obtained when the content of PANI nanofibers was 3 wt%, which was 46.44% higher than that of pure PVDF membrane. The maximum thermal conductivity of composite membranes after alignment was 84.5% greater than that of pure PVDF membrane when the content of PANI nanofibers was 50 wt%. The composite membrane is a promising new potential material in heat transfer field and the mechanism explored in this study would be informative for further development of similar thermal conductive polymeric materials.

Micro-fibril cellulose as a filler for glass fiber reinforced unsaturated polyester composites: Fabrication and mechanical characteristics

The waste produced by bamboo stick production processing was collected from a Vietnamese craft village and used as a source of microfibril cellulose (MFC) for a filler of unsaturated polyester (UP) resin based composites in this study. A mixture of MFC in UP was obtained by directly introducing the bamboo pulp into UP resin followed by a grinding process using a ball-grinding machine. A master batch method was also adopted for composite preparation, in which a high-content solution of MFC in UP resin was first fabricated and then diluted to prepare another solution with the desired content. Morphology and mechanical characteristics of UP resin based composites were investigated. Effect of different methods of preparation, such as hand lay-up and vacuum bagging methods, on the mechanical properties of glass fiber reinforced UP resin composites was also examined, showing that the tensile strength of composite materials with 0.3 wt% MFC was increased by 10.24% (for the hand lay-up method) and 19.62% (for the vacuum bagging method) when compared with the pristine composite material. The flexural strength increased from 192.40 MPa to 208.63 MPa and the impact strength increased by 19.6% from 158.28 kJ/m2 to 186.84 kJ/m2 for the hand lay-up method.

USAGE OF CANDLE NUT SHELL WITH POWDER SIZE OF D

Recently around 60% of the hazelnut shell has the potential to become wasted material. The purpose of this research is to exploit waste hazelnut shell by examining the mechanical properties of composite from the powder of hazelnut shell. Epoxy resin acts as a matrix mixed with a hazelnut shell powder as a filler with a composition of 20%, 30% and 40% wt. Both materials are mixed using a mechanical mixer with varying speed and stirring times. The resulting composite material is then tested by tensile, impact and hardness testing. The Taguchi method is used to optimize forming process parameters of the epoxy-powder hazelnut shell composite. Research shows that the forming process parameters give different effects for each different mechanical property. Research found out maximum tensile strength of composite material at 30% wt of powder hazelnut shell. Overall, the result of taguchi optimization for the forming process parameters in this study was 43.68 N/mm2 for tensile strength, 0.074 106 J/mm2 for impact strength and 98.57 SHN for hardness.Keywords: .

Modelling of Creep and Stress Relaxation Test of a Polypropylene Microfibre by Using Fraction-Exponential Kernel

A tensile test until breakage and a creep and relaxation test on a polypropylene fibre are carried out and the resulting creep and stress relaxation curves are fit by a model adopting a fraction-exponential kernel in the viscoelastic operator. The models using fraction-exponential functions are simpler than the complex ones obtained from combination of dashpots and springs and, furthermore, are suitable for fitting experimental data with good approximation allowing, at the same time, obtaining inverse Laplace transform in closed form. Therefore, the viscoelastic response of polypropylene fibres can be modelled straightforwardly through analytical methods. Addition of polypropylene fibres greatly improves the tensile strength of composite materials with concrete matrix. The proposed analytical model can be employed for simulating the mechanical behaviour of composite materials with embedded viscoelastic fibres.

English

Composite materials are being used extensively in different realms of science for various applications. There use is prominent in the aerospace industry. The testing of these composite materials is of substantial importance, as they might be susceptible to failure due to the variation in the temperature ranges and the cryogenic temperatures which the materials have to endure. In the present work, the tensile strength of composite materials are observed using double walled vacuum chamber which is designed for the Universal Testing Machine (UTM). Man has still not quenched his inquisitiveness about outer space which has led to constant advancement in the materials used in space-crafts. Composite materials exhibit properties which makes them suitable for uses at cryogenic temperatures. In the present world scenario, where space exploration and research are of great relevance to every nation, it is the need of the hour for science congregants to take the next big leap in design and manufacture of spacecraft and the materials used in the different