Compressive Strength Of Composites Research Articles

Influence of Microstructure Randomness on the Shear Behaviour and Compressive Strength of Continuous Carbon Fibre Composites

Influence of Microstructure Randomness on the Shear Behaviour and Compressive Strength of Continuous Carbon Fibre Composites

Effect of Fiber Content on the Mechanical Properties of Jute Fiber Reinforced Perlite/Gypsum Composites

Fiber reinforcement is one of the ways for the improvement of the mechanical properties of composite materials. Previously, it was seen that the fiber content in composites played a vital role in the mechanical properties of fiber-reinforced composites. Considering the benefits of natural fiber, in this work, jute fiber reinforced perlite/gypsum composites were manufactured with five different fiber contents ranging from 2.41 % to 4.82 %. The ratios of gypsum to perlite and gypsum to water were kept constant, and only fiber content was varied. The compression and flexural tests were conducted to investigate the effect of jute fiber content on the mechanical properties of jute fiber-reinforced perlite/gypsum composites. Results showed that both the compressive and flexural properties were improved up to certain jute fiber content. The compressive strength, modulus, and energy absorption of the jute fiber-reinforced composite were found to be the maximum at 3.01 % fiber content. The compressive strength of the composite with 3.01 % jute fiber content was 35.23 % higher than the composite with 2.41 % fiber content. The flexural strength, modulus, and energy absorption were maximum at 3.61 % jute fiber content. This study demonstrated that the addition of jute fiber to perlite/gypsum composites results in improved mechanical properties up to a certain percentage of jute fiber, beyond which the properties deteriorate.

Effects of the addition of short straight steel fibers on the strength and strains of high-strength concrete during compression

The article presents the effect of the addition of short straight steel fibers on the behavior of high-strength concrete (HSC) under compression (σ–ε curves). Deformations of cylindrical samples were measured simultaneously with the use of linear variable differential transformers (LVDT), strain gauges and the method of digital image correlation (DIC). The study showed that as the content of short straight steel fibers increases, both the composite compressive strength (fc) and strains (ε0), which correspond to the stress equal to the compressive strength, increase as well. To a lesser extent, the effect of short straight fibers on the descending part of the σ–ε curve was observed. An increase in the density and toughness ratio of the compressive strength of high-strength concrete with fibers compared to concrete without fibers was also observed. Moreover, compressive strength of the composite was estimated using the ultrasonic method. Based on the obtained results, a statistical analysis and an estimation of parameters fc and ε0 were carried out, and an analytical model was proposed to describe σ–ε relationship for HSC reinforced with short straight fibers under compressive loading. The results obtained for compressed fiber-reinforced concrete were compared with data available in literature.

Study on Coordinated Deformation Failure Mechanism and Strength Prediction Model of Rock-lining Concrete

Shotcrete has been widely used in the excavation of caverns and tunnels as a key load-bearing element in the support system. However, the interfacial stresses and bond strengths within the composite structures formed by the interaction of geologic bodies and tectonic formations are not well understood, which can lead to safety accidents and excessive wastage of support materials in engineering. To address this gap, rock-concrete composite specimens were created using six distinct types of surrounding rocks. The strength law of composite specimens was analyzed, and the uniaxial compressive strength prediction model of composite specimens was derived based on Mohr−Coulomb strength yield criterion. The results show that the uniaxial compressive strength of the composite specimen changes with the change of rock type, which is between the strength of rock and concrete. The uniaxial peak strength and elastic modulus of composite specimens are linearly positively correlated with the ratio (Y) of concrete-rock elastic modulus, which is easily affected by concrete properties. However, the peak strain is linearly and negatively correlated with Y, which is greatly influenced by rock. The rock-concrete interface of the composite specimen plays an important role in the failure of the specimen, which changes the stress transfer state of the composite specimen, produces uncoordinated deformation, and finally causes the failure of the specimen. The theoretical and test value error of the derived composite specimen uniaxial compressive strength prediction model are –1.19%~12.20%, and the theoretical calculation model can be used to predict the uniaxial compressive strength of rock-concrete composite specimens.

In-situ preparation of porous metal-ceramic composite from secondary aluminum dross and red mud for adsorption of organic pollutant

Secondary aluminum dross (SAD) and red mud (RM) are solid waste discharged from aluminum industry. SAD contains 10–25 wt% aluminum nitride (AlN) and RM contains 20–50 wt% iron oxide. In this work, porous metal-ceramic composite was in-situ made from SAD and RM. Iron oxide was reduced into Fe2Si by AlN, and the generated nitrogen created pores. It was studied that effect of raw material and thermal treatment on pore structure and properties of the composite. Porosity, bulk density and compressive strength of composite were 65.78%, 1.03 g/cm3 and 17.77 MPa, when SAD content was 40 wt% and sintering temperature was 1450 °C. About 95.9% of malachite green in waste water was adsorbed by composite after 24 h. The composite could be recycled by magnetic separation after adsorption, attributed to the magnetic Fe2Si. This work proposed a novel idea of making recyclable porous material for adsorption of organics in waste water.

Investigation of the microstructure and mechanical properties of an Al/SiC/ZrO2 hybrid composite by spark plasma sintering technique

The quantum of work with silicon carbide (SiC) and zirconium dioxide (ZrO2) in the aluminum hybrid composite material has increased due to the growing demand for lightweight materials for various industrial applications. The aluminum hybrid composite with the wt% of primary reinforcement particles of SiC was kept constant at 5%, and the secondary reinforcement particles of ZrO2 were taken by 5%, 10%, and 15%. The sintering parameters were used as the temperature at 600°C, holding time of 35 minutes, and pressure at 30MPa. In this work, the aluminum composite material reinforced with 5%wt of SiC particles compared the test results with aluminum hybrid composite reinforcement of SiC and ZrO2 nanoparticles. Adding ZrO2 reinforcements enhances the aluminum hybrid composite material's better microstructure, microhardness, tensile strength, compression, and yield strength.

Experimental Investigations on the Development of Hybrid Metal Matrix Composite of Al7075 on Microstructural, Mechanical, and Dry Sliding Aspects

Abstract This research work aims to synthesize a hybrid Al7075 metal matrix composite reinforced with sustainable and synthetic reinforcement. With the employment of an ultrasonic transducer, two-stage stir casting is used to synthesize composite materials. The prepared samples were machined and polished for mechanical, tribological, and microstructural characterization. Optical microscopy and field emission scanning electron microscopy with elemental mapping were used to analyze the microstructure of the composite material. The microstructural examination revealed the homogeneous dispersion of reinforcement particles throughout the matrix. With the incorporation of reinforcement, the synthesized composite's compressive strength and micro-hardness were both increased, and the highest values were found to be 569.172 MPa and 178.86 HV, respectively, in one of the samples (B3 sample) as compared to as-cast Al7075 alloy. Tribological examination of composite samples shows that wear-rate enhances with an increase in the content of reinforcement. The wear resistance of sample B3 is highest among all prepared composite samples. Wear debris, grooves, micro-cracks, and small pits were observed on the worn-out surfaces of the samples by field emission scanning electron microscope analysis.

AN INVESTIGATION ON THE MECHANICAL AND TRIBOLOGICAL PROPERTIES OF AN ULTRASONIC-ASSISTED STIR CASTING AL-CU-MG MATRIX-BASED COMPOSITE REINFORCED WITH AGRO WASTE ASH PARTICLES

This research work reports the influence of 3-μm-sized Palm Sprout Shell Ash (PSSA) reinforcement on the mechanical and tribological behavior of the Al-Cu-Mg alloy. Composites of varying weight percentages of reinforcement ranging from 1 to 6 at intervals of 1 Wt.% were produced using the ultrasonic-assisted bottom-poured stir casting technique. Microstructural studies, mechanical testing, and wear properties analysis were performed on the alloy and the synthesized composites. The microstructure of the obtained samples was examined using Scanning Electron Microscope, Energy Dispersive Spectroscopy (SEM/EDS), and XRay Diffraction (XRD). The XRD patterns provided confirmation of the presence of PSSA (SiO2 and Al2O3) particles. The addition of PSSA reinforcement has significantly improved the hardness, tensile strength, and compression strength of composites. The hardness, ultimate tensile strength, and compression strength were improved by 13.89%, 24.04%, and 32.93%, respectively, with the 6 Wt.% PSSA-reinforced composite. However, the incorporation of reinforcement has resulted in a decrease in the ductility of the Al-Cu-Mg alloy composite; the maximum decrement of 42.87% was with the 6% PSSA-reinforced composite. Tests were conducted at different loads and speeds to evaluate the wear behavior of the prepared samples. Superior wear resistance was observed in the composites. The fracture and wear mechanisms of reinforced and unreinforced were observed using SEM.

Evaluation and optimization of mechanical properties of laterized concrete containing fly ash and steel fiber using Taguchi robust design method

The present study employs the S/N ratio and multiple regression analysis to evaluate the mechanical properties of laterized concrete with fly ash and steel fiber. The study considers compressive, split tensile, and flexural strengths as responses at 7 and 28 days. The Taguchi L16 (4 *4) orthogonal array experimental design is applied to optimize the performance of mechanical properties of concrete by using the design of experiments. The replacement of 25% of the granite aggregate with laterite aggregate resulted in a 12.44% increase in the strength of M30-grade concrete after 28 days. The composite's compressive strength decreases when the replacement level exceeds 25%. The split tensile and flexural strengths of the composite showed an increase of 14.54% and 16.93%, respectively, compared to the control mix. Furthermore, the test outcomes for durability factors like drying shrinkage and rapid chloride penetration in steel fiber reinforced fly ash-based lateritic concrete mixes with a 50% replacement rate adhere to the prescribed standards, verifying their designed performance over the designated structural lifespan. However, after multiple regression analysis, it is found that the error related to the correlation between experimental and analytical value strength is about 5%. Microstructural studies of the ideal mix were performed at 28 days to further understand the morphology of the laterized concrete containing fly ash and steel fiber.

Robust anti-impact, energy absorption and thermal properties of polyurethane nanocomposites modified by phenol-amine chemistry

It is still a considerable challenge for polyurethane elastomers (PUE) to possess outstanding mechanical and thermal performance simultaneously against harsh dynamic impact environment due to their heat accumulation, thermal stress softening and mechanical failure. Thus, this article innovatively prepared binary nanofibers composed of carbon nanofiber (CNFs) and aramid nanofibers (ANFs) to reinforce PUE, where catechol (CC) and polyethyleneimine (PEI) were served as interfacial modifier between nanofibers and polymer matrix. PUE with 1.5 wt% binary nanofibers achieve 31.62 % increase in crosslinking density, 146.8 °C improvement in thermal decomposition temperature compared to Neat PUE. Besides, the absorption energy and dynamic compression strength of composites were increased by 40.36 % and 38.26 %, respectively. Because reinforced nanofibers with crosslinking network structures improve the interface interaction between fillers and matrix, facilitate stress transfer and increase the energy threshold of thermal decomposition. The paper supplements the impact resistance analysis of PUE-based protective materials under impact loads, providing a systematic and scientific reference for the design and manufacture of impact resistant materials.

Influence of Heat Treatment on the Mechanical Properties and Precipitation Kinetic of Sugar Palm Fiber Ash Reinforced LM26 Al Matrix Composites

Heat treatment is a commonly known treatment subjected to aluminum alloy and their composites to improve their mechanical properties for automotive, aerospace, and marine applications. The heat treatment was carried out to determine the influence of aging time and temperature on the mechanical properties of LM26 Al alloy reinforced with 0, 2, 4, 6, 8, and 10 wt% sugar palm fiber ash (SPFA) and its precipitation kinetics. The LM26 Al/SPFA composites were fabricated through the stir casting technique, solutionized at 500oC for 2 h, and quenched in water at room temperature. The quenched composites were aged at various ageing times and temperatures and allowed to air cool. The hardness, impact energy, tensile, and compression strengths of the aged composites were appraised. In addition, the precipitation kinetics were studied to validate the precipitation temperatures of LM26 Al matrix composites. The hardness of the composites increased with aging time and temperature, with LM26 Al/10 wt% SPFA composite reaching a hardness peak of 102.10 VH at an aging temperature of 180oC after 5 h, compared to 56.70 VH for LM26 Al alloy. Similarly, after 5 h of aging at 180oC, the LM26 Al/8 wt% SPFA composite achieved maximum tensile and compression strengths of 198.21 MPa and 326.22 MPa, respectively. Precipitation temperature decreased from 584.8oC (LM26 Al alloy) to 480.46oC (LM26/ 10wt% SPFA), indicating that adding SPFA improved precipitation kinetics. The age-hardened composite with high hardness, tensile strength, and compression strength makes it a promising piston material application in the automotive industry.

Impact Energy Absorption of Sisal Fiber Reinforced Ferrocement Slab Elements and Its Statistical Relationship with Composite Compressive Strength

Impact Energy Absorption of Sisal Fiber Reinforced Ferrocement Slab Elements and Its Statistical Relationship with Composite Compressive Strength

Polipropilen Lif Türü, İçeriği ve Uzunluğunun Sert Poliüretan Kompozitlerin Mekanik Performansına Etkisi

The purpose of this work is to improve mechanical properties of rigid polyurethane (RPU) composites used in traditional ceramic casting industry. Therefore, monofilament (mono) and fibermesh (fibril) polypropylene (PP) fibers with various lengths (3, 6, 12 and 18 mm) were incorporated to polymer matrix at different rates (0.5, 1.0, 1.5 and 2% by weight). Effects of fiber type and content on flexural strength, bending strength and compressive strength of composites were investigated. Surface morphology and thermal characteristics of composites were evaluated by SEM and TGA analysis, respectively. Bulk densities of specimens with and without PP fibers vary between 72,15-146 kg/m3. Compared to pure rigid polyurethane foam, bulk density of monofilament PP reinforced composites significantly increased and the highest density value (146,86 kg/m3) was reached in M6/2.0 sample. On the other hand, incorporation of fibrilmesh caused a decrease in bulk density. While the increase in percentage of mono PP increased flexural strength, the presence of fibril PP had a negative effect on strength. Compressive strength of all mono PP reinforced composites is higher than that of pure RPU, except for M6/0.5 sample. Besides, SEM analysis revealed that the presence of PP fibers generally reduced number of closed cells in composite structure. Experimental findings indicate that fiber type, content and length affect mechanical performance of RPU composites. In addition, it is possible to use mono PP fiber reinforced RPU composites as support apparatus in ceramic casting industry.

Metallic Iron or a Fe-Based Glassy Alloy to Reinforce Aluminum: Reactions at the Interface during Spark Plasma Sintering and Mechanical Properties of the Composites

The microstructural features and mechanical properties of composites formed by spark plasma sintering (SPS) of Al + 20 vol.% Fe and Al + 20 vol.% Fe66Cr10Nb5B19 (glassy alloy) mixtures composed of micrometer-sized particles are presented. The interaction between the mixture components was studied by differential thermal analysis and through examining the microstructure of composites sintered at two different SPS pressures. When the pressure was increased from 40 MPa to 80 MPa, the thickness of the reaction products formed between the iron particles and aluminum increased due to a more intimate contact between the phases established at a higher pressure. When the metallic glass was substituted for iron, the pressure increase had an opposite effect. It was concluded that local overheating at the interface in the case of Al + 20 vol.% Fe66Cr10Nb5B19 composites governed the formation of the product layers at 40 MPa. The influence of the nature of reinforcement on the mechanical properties of the composites was analyzed, for which sintered materials with similar microstructural features were compared. In composites without the reaction products and composites with thin layers of the products, the hardness increased by 13–38% relative to the unreinforced sintered aluminum, the glassy alloy and iron inclusions producing similar outcomes. The effect of the nature of added particles on the hardness and compressive strength of composites was seen when the microstructure of the material was such that an efficient load transfer mechanism was operative. This was possible upon the formation of thick layers of reaction products. Upon compression, the strong glassy cores experienced fracture, the composite with the glassy component showing a higher strength than the composite containing core-shell structures with metallic iron cores.

Characteristics of Carbon-Fiber-Reinforced Polymer Face Sheet and Glass-Fiber-Reinforced Rigid Polyurethane Foam Sandwich Structures under Flexural and Compression Tests.

Composite sandwich structures are extensively used in aircraft applications. Aircraft components are required to be robust and lightweight. Sandwich structures made of carbon-fiber-reinforced polymer as the facing sheets and milled-glass-fiber-reinforced rigid polyurethane foam with a different glass fiber content as the core structure were prepared. The influence of glass fiber content in the foam on the sandwich structure's mechanical properties was investigated. Flexural and compression tests were performed to assess the mechanical properties of the sandwich structures. Visual inspection and an optical microscope were used to observe the morphology of the polyurethane composite foams at different contents. From the flexural test, the force, facing stress and core shear stress improved with the increase in the milled fiber loading with the maximum increase at 10 wt.% loading and then a drop. Meanwhile, the compression modulus and strength increased up to 20 wt.% loadings and then dropped subsequently. The increase in the polyurethane composite foam's compression strength shifted the bending load's failure type from facing crack failure into core shear failure. The loadings range of 8-10 wt.% showed a transitional of the bending loading failure type. The density of the foams increased with the increase in milled glass fiber loading. At 10 wt.% loading, the density increased by 20%, and it increased by 47% at 30 wt.% loading. At 30 wt% loading, the optical microscope images of the foam showed wall thinning and broken walls that were responsible for the drop in the mechanical properties of the sandwich.

Out‐of‐plane compression properties and failure mechanism of gradient 3D woven composites

AbstractGradient three‐dimensional (3D) orthogonal preforms with low‐ and high‐density regions were manufactured through the flexible oriented 3D woven process (FO3DWP) at different fiber volume fractions and z‐yarn contents. The layer porosity distribution of preforms was regulated by modifying fiber tension and measured using micro‐computed tomography (micro‐CT) technology. After impregnation with epoxy resin, the out‐of‐plane compression properties of gradient 3D woven composites were evaluated. The results indicated that the out‐of‐plane compression strength could be improved by the gradient design. In particular, the gradient composite with a fiber volume fraction of 0.46 and z‐yarn volume fraction of 0.05 exhibited the highest compression strength at 470 MPa. Furthermore, failure morphologies were analyzed using micro‐fracture photographs and scanning electron microscopy (SEM). The gradient design efficiently protected the interface between z‐directional fibers and the matrix by minimizing z‐yarn bending. However, the compression strength of 3D woven composites decreased as the z‐yarn content increased from 0.05 to 0.15, due to the increased bending of the z‐directional fibers during the compression test.

Influence of printing-based factors on the mechanical properties of hexagonal lattice-structured 3D printed novel walnut shell/polylactic acid composite

The incorporation of bio-based natural fillers and lattice structures in thermoplastic polymer has superior advantages such as a reduction in the usage of conventional polymers with improved damping and mechanical properties. The present work focuses on the development of Walnut Shell/PLA (WSP) lattice-structured composite by the Fused Filament Fabrication technique. The flexural strength, compression strength, and thickness error properties of the hexagon lattice-structured WSP composites are optimized by varying Printing-Based Factors (PBFs) which include infill density (60%, 80%, and 100%), nozzle temperature (190°C, 210°C, and 230°C), printing speed (10 mm/sec, 20 mm/sec, and 30 mm/sec), and layer height (0.1 mm, .2 mm, and .3 mm). The flexural and compression test experiments were conducted as per the ASTM D790 and ASTM D695 standards. The process optimization of the measured responses is made by using Taguchi grey relational grade optimization technique. The experimental outcomes such as compressive and flexural strength and minimal dimensional error are converted into the Grey Relational Grade (GRG) for the optimization process. The results show that the Signal-to-Noise ratio (S/N) from the measured GRG clearly shows that, the lower layer height of 0.1 mm, higher nozzle temperature of 230°C, higher infill density of 100%, and average printing speed of 20 mm/sec is an optimal experimental condition for attaining higher strengths and lower errors. From the Analysis of Variance (ANOVA) analysis, the printing temperature, and layer height are the most persuasive PBFs for the mechanical and physical characteristics with respect to the incorporated lattice structure. The optimized experimental conditions develop maximum flexural and compressive strengths of 4.98 MPa and 28.19 MPa, in addition to a lower thickness error of .186 mm obtained for hexagon lattice-structured WSP biopolymeric composites.

Effect of Boron Carbide Particles Addition on the Mechanical and Wear Behavior of Aluminium Alloy Composites

In this research, synthesis and assessment of the mechanical and wear possessions of Al7049-nano B4C composites are determined by experiments. Using the liquid metallurgy route, a stir casting technique was used to create composites with increasing concentrations of nano B4C from 3 to 9 weight %. Each composite’s reinforcement particles were heated to 400 degrees Celsius before being added to the molten Al7049 alloy in two separate steps, i.e., two-stage stir casting to optimise wettability and distribution. Scanning electron microscopy (SEM) was utilised to examine the microstructure, and energy dispersive spectroscopy (EDS) was utilised to determine the elemental make-up. Mechanical characteristics of composites were determined by subjecting them to tensile, compression, and hardness tests. Wear tests were conducted as per ASTM G99 standards with varying loads and speeds. Nanosized B4C particles were found to be dispersed throughout the sample space in a microstructural analysis. Hardness, ultimate strength, yield strength, and compression strength of Al7049 alloy composites were found to increase significantly as the weight percentage of nano B4C was increased. Additionally, compared to the unreinforced form, the ductility of the Al7049 alloy composites was slightly reduced. SEM micrographs of tensile-fractured specimens were used for research into the field of tensile fractography. Nano B4C reinforced composites exhibited superior wear resistance as compared to Al7049 alloy. These prepared composites can be used for wing root fitting of an aircraft.

Effect of expanded perlite addition on the thermal conductivity and mechanical properties of bio-composites with hemp-filled

In the world, environmental pollution has increased due to industrialization. To reduce environmental pollution, the use of hemp, which has a low environmental impact and is known for its carbon-negative feature, has gained importance in the production of composites. The aim of this research is to develop a bio-composite lightweight building material using expanded perlite (EP) and hemp stalks. In this study, 11 different mixtures were produced by using polyester matrix as binder, hemp and EP as filling material. These produced bio-composites' physical, mechanical, and thermal conductivity were examined. The results show that while the increase in the amount of filling in the composite, there are decreases in apparent density, compressive strength, ultrasonic pulse velocity (UPV) and thermal conductivity. However, there was an increase in water absorption, swelling in thickness (ST) and weight loss (WL) values. The water absorption, UPV, and compressive strengths of composites were increased, while the thermal conductivity was decreased, by the addition of EP. The lowest thermal conductivity value was reached as 0.1093 W/mK in the H35P5-coded specimen. In addition, the highest compressive strength value was reached as 35.175 MPa in the H25P5-coded specimen, except for the reference specimen. According to the thermogravimetric analysis results the addition of EP and hemp caused the thermal stability of the composite to deteriorate at lower temperatures. The results showed that sustainable biocomposites from EP and hemp stalks can be used as thermal insulation materials. Also the use of carbon-negative hemp with a low environmental impact makes the study important.

Investigating the mechanical properties of tungsten carbide metal matrix composites with Al 6061

In the present study, attempts were made to synthesis nano-WC-reinforced Al6061 alloy composites using the squeeze casting process with varied weight percentages (2 wt%, 4 wt%, and 6 wt%) and compared to as cast Al6061 alloy. Using SEM and ASTM standards, the morphology and mechanical behaviour of the produced nano composite were evaluated. The microstructure of synthesised nanocomposites reveals an almost equal distribution of reinforcing particles throughout the matrix alloy, with no trace of residual pores. In comparison to the monolithic aluminium alloy, the nano composite's ultimate tensile and compressive strengths were determined to be 16.34% and 32.63%, respectively. Three-point bending tests were conducted to determine the bending behaviour of the hybrid composites. Due to the high dislocation density in the matrix and the huge variation in Young's modulus, the flexural strength (51.8%) of the composites improved significantly. Impact testing were conducted according to ASTM E23. Due to decreased porosity and better grain refinement, it was determined that the synthesised hybrid composites were considerably enhanced (42.8%).