Tensile Strength Values Research Articles

Improvement of mechanical performance via interfacial strengthening of carbon fiber‐epoxy reinforced hybrid laminate by incorporation of functionalized graphene nanoplatelet interphase

AbstractThis study is an attempt to develop high‐quality hybrid composites via functionalization (for homogeneous distribution) of the graphene nanoplatelets (FGNP) and then doping to carbon fiber reinforced especial aviation epoxy matrix (Araldite LY5052) via vacuum bagging molding (VBM). The utilized materials were characterized by UV–Vis spectroscopy, tensile, impact, hardness tests, and fracture mode analysis using a scanning electron microscope (SEM). The results revealed a 92% (502.5 MPa) and 85% (490 MPa) improvement in tensile strength values by doping the 1 and 1.5 wt% FGNPs, respectively. There was an improvement in impact strength with the addition of FGNP; a 28% (3.23 J/mm2) increase was achieved in the nanocomposite with 1 wt% FGNP added, and there was a decrease again in the nanocomposite with 1.5 wt% FGNP added. However, it was still 12% (2.83 J/mm2) better than the neat composite. In addition, the results of examining the fractured surface structures of the impact and tensile test specimens were compatible with these results. It reveals a significant separation of fiber‐matrix bonds with 1.5 wt% FGNP contribution. While tensile and impact strengths peak at 1 wt% FGNP value and decrease afterward, hardness values increase in parallel with the increase in FGNPs.Highlights Composites were developed by functionalized graphene nanoplatelets (FGNP). The fiber‐matrix interface was strengthened with FGNP interphase. A 92% tensile strength increase was achieved with 1 wt% FGNP additives. 28% in impact strength and 55% in hardness increase by 1 wt% FGNP. The morphology confirmed that the FGNP interphase filled the interface.

On demand thermal surface modification of carbon fiber for improved interfacial shear strength

A thermally triggered, on demand, surface modification method was exploited using carbon fibers (CFs). Bisdiazomethanes undergo thermal activation to generate extremely reactive carbene intermediates, able to react with the CF surface. Herein, the surface modification of continuous CFs is demonstrated by dipping the fibers in a solution of bisdiazomethane at three different concentrations of 1 mmol, 5 mmol, and 10 mmol, followed by air drying and heating at 120 °C. Tensile strength and Young's Modulus values were preserved in the treated fibers, while the interfacial shear strength (IFSS) values showed significant improvement. The highest IFSS improvement was found (189 %) for the fibers dipped in the 5 mmol solution, with significant increases noted for the 1 and 10 mmol modifications, of 54 % and 97 %, respectively. When the thermal modification was repeated with parameters analogous to a sizing application used in CF manufacture (30 s dip, 2-min heating), 74–79 % improvements in IFSS resulted. Hence, this approach can serve as a simple, scalable, and tunable surface modification method for discontinuous CFs that promotes their use in high value applications.

High-Strength, Self-Healing Copolymers of Acrylamide and Acrylic Acid with Co(II), Ni(II), and Cu(II) Complexes of 4′-Phenyl-2,2′:6′,2″-terpyridine: Preparation, Structure, Properties, and Autonomous and pH-Triggered Healing

The utilization of self-healing polymers is a promising way of solving problems associated with the wear and tear of polymer products, such as those caused by mechanical stress or environmental factors. In this study, a series of novel self-healing, high-strength copolymers of acrylamide, acrylic acid, and novel acrylic complexes of 4′-phenyl-2,2′:6′,2″-terpyridine [Co(II), Ni(II), and Cu(II)] was prepared. A systematic study of the composition and properties of the obtained polymers was carried out using a variety of physicochemical techniques (elemental analysis, gel permeation chromatography (GPC), attenuated total reflectance Fourier transform infrared spectroscopy (ATR/FT-IR), ultraviolet-visible spectroscopy (UV-vis), small-angle X-ray scattering (SAXS), wide-angle X-ray scattering (WAXS), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), dynamic mechanical analysis (DMA), confocal laser scanning microscopy (CLSM), and tensile testing). All metallopolymer samples exhibit autonomous intrinsic healing along with maintaining high tensile strength values (for some samples, the initial tensile strength exceeded 100 MPa). The best values of healing efficiency are possessed by metallopolymers with a nickel complex (up to 83%), which is most likely due to the highest lability of the metal–heteroatom coordination bonds. The example of this system shows the ability to re-heal with negligible deterioration of the mechanical properties. The possibility of tuning the mechanical properties of self-healing films through the use of different metal ions has been demonstrated.

Investigating the influence of ferric oxide grade alumino‐silicate cenosphere particulates and heat treatment on the microstructural evolution and mechanical properties of Al6061/ferric oxide alumino‐silicate cenosphere (x weight %) composite

AbstractThe main aim of this investigation is to fabricate aluminum 6061 composites with three different weight percentages of ferric oxide grade alumino silicate cenosphere (1 wt.%, 3 wt.%, and wt.%) by the stir‐casting process. The fabricated cast composite and T6 heat‐treated composite is used to obtain a fundamental understanding of various weight percentages of the cenosphere and the influence of heat treatment on the microstructural changes, mechanical characteristics, the mechanism of fracture, and the interface between the aluminum‐matrix and ferric oxide grade alumino‐silicate cenosphere particulates. Tensile and compressive tests with a constant strain rate (0.5 mm ⋅ min−1) were carried out to study the strength and to find a correlation between the various weight fractions of cenosphere and heat treatment. Investigations of the changes in the microstructure of the aluminum ferric oxide grade alumino silicate cenosphere composite and the fractography of the fracture surface are investigated using optical and scanning electron microscope. X‐ray diffraction was utilized to confirm the results obtained from optical and scanning electron microscope analyses for phase characterization validation. A maximum of 30 % increase in hardness value, 20 % increase in tensile strength value, 33 % increase in maximum compressive strength value, and 2 % increase in elongation values are observed in heat‐treated composite when compared to cast composite.

Non-standard adhesives for wood-based composites: powder adhesives and bicomponent fibers

Powder adhesives and bicomponent fibres are widely used for composite manufacturing; mainly, they are used for glueing fibres during non-woven production. However, in the woodworking industry, they are rarely used. This study aims to investigate the possibility of powder adhesive and bicomponent fibres utilisation for gluing wood. For this purpose, epoxy-polyester powder adhesive and polyester (PES) bicomponent fibres were selected, and one-component moisture-curing polyurethane adhesive was used as a reference. The selected wood species were spruce, beech, oak and wenge. The differences between powder adhesive- and bicomponent fibre-glued wood joints were observed using scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDX). Mechanical properties of glued wood joints were characterised by tensile shear strength and modelled using finite element modelling (FEM). The adhesives were further characterised using Fourier-transform infrared spectroscopy (FTIR) and differential scanning calorimetry (DSC). The wood joints produced by all combinations of selected wood species and adhesives were comprehensively characterised. The highest values of tensile shear strength were reached by powder epoxy-polyester adhesive (14.85 MPa), whereas joints bonded by bicomponent fibres (5.19 MPa) reached lower values than reference samples.

Mechanical and Tribological Properties of Carbon Fiber Reinforced POM Composite Filled With Maleamidic Acid Treated Carbon Nanotube

ABSTRACTIn order to attain improved mechanical properties of the carbon fiber (CF) reinforced polyoxymethylene (POM) composite, maleamidic acid treated carbon nanotube (CNT) was deposited on carbon fiber. The mechanical properties of composites have been investigated. The tensile strength values of the treated CF/POM composites at all CNT mixing ratios are found to be higher than that of untreated one. The surface morphologies of the fractured surfaces of the composites were recorded using scanning electron microscopy (SEM) to gain information about the fiber–matrix interfacial adhesion in the composites. The friction coefficient of all the CF/POM/CNT composites decrease as the load increases from 10 to 20 N under the same sliding speed of 1000 r/min. XPS results showed that the formation of C–O, C=O, and O–C=O based species give rise to chemical bonds of the CF and the POM.

Mechanical Properties of PVA/Alginate Membranes Fabricated using Electrospinning as A Wound Dressing

Alginate is an interesting natural biopolymer due to its many benefits and good biological properties. Observing the mechanical properties of PVA/Alginate fibers made by electrospinning machines can help predict their behavior and measure their performance under various conditions including applied external forces. Therefore, this study investigated the elastic properties of PVA/Alginate membranes, specifically tensile strength and elongation. The fabrication material used is PVA / Alginate solution with a PVA solution concentration of 20% and alginate solution 2.5%. The electrospinning process is carried out by optimizing at a voltage of 25 kV, the distance between the spinneret end and the collector is 15 cm, the flow rate is 130, and the spinneret diameter variations are 0.4 mm, 0.6 mm, and 0.8 mm. To determine the morphology of the fiber surface, observations were made using ocular microscopes and SEM. From this observation, it is known that the morphology formed using a 0.4 mm spinneret has the tightest structure among the three sizes of spinneret diameter. To determine the effect of spinneret diameter on the value of tensile strength and elongation, tensile strength tests are carried out. The tensile strength and elongation values of the membrane obtained with variations in spinneret diameters of 0.4 mm, 0.6 mm, and 0.8 mm are 1.96 MPa, 3.77 MPa and 6.11 MPa respectively and the elongation values are 17%, 52.7%, and 97%. With medical material standards, it has a tensile strength value between 1 MPa – 24 MPa and an elongation value between 17% – 207%, so that PVA / Alginate fiber membranes have the potential to be applied as wound dressings.

Durability and hardened characteristics of cement mortar incorporating waste plastic and Polypropylene exposed to MgSO4 attack

Annual waste plastic disposal has grown, harming nature. Utilising this waste in concrete production may help preserve building resources. This study tested cement mortar with polyvinyl chloride (PVC) and polypropylene (PP) substituted for sand aggregate at 0, 5, 10, 15, and 20%. The samples were nevertheless exposed to a 10% and 20% MgSO4 solution for a month. The properties of both fresh and hardened materials under these circumstances have been evaluated and contrasted with those evaluated under typical circumstances. For mixes including PP and PVC, the flow diameter increased. The rounded plastic particles provided fewer contact surfaces and less friction among mixtures, which reduced water consumption and improved workability, leading to an increase in slump flow. As the amount of plastic aggregate increases, the compressive strength decreased. Moreover, this pattern might be explained by the weakening of the bond between the surfaces of the plastic aggregate and cement paste. The hydration of cement may also be hampered by the hydrophobic properties of plastic aggregate. Like compressive strength, the splitting tensile strength decreased as the replacement level of plastic ratio increased regardless of its type under all conditions (normal and exposing to MgSO4). PP and PVC fine aggregate in mortar increases sorptivity under all situations. Following screening, those circumstances and PVC have the most impact on compressive strength. increasing PVC and PP at 10% for each of them leads to lower values of compressive and tensile strength. An optimization process was implemented to determine the optimum value of PVC, PP, and MgSO4. It shows that using PVC of 3.9%, PP of 10.1%, and MgSO4 of 19.59% leads to maximum compressive and tensile strength with the minimum cost and CO2 emissions.

A novel cobweb-like sub-grain structured Al-Cu-Mg alloy with high strength-plasticity synergy

Al-Cu-Mg alloys, as the most widely used lightweight structural materials, have been recognized as promising candidates in the transportation field for a low-carbon economy. However, the tensile strength and plasticity of alloys cannot be simultaneously improved to satisfy the requirements of continuously upgraded transportation vehicles. In this work, inspired by high-tensile strength and high plasticity of cobweb structure, a novel cobweb-like sub-grain structure was developed in Al-Cu-Mg alloys by a successive solution, high-strain-rate rolling (4.4 s-1), cryogenic treatment (–196°C) and aging process (SRCA). Notably, the tensile strength and plasticity of this alloy were superior to those reported in the current study. An ultrahigh Vickers hardness and tensile strength value of 206.2 Hv and 619.6 MPa, which were 39.8% and 31.8% higher than those of traditional T6 heat-treated Al-Cu-Mg alloys, were obtained after SRCA. Meanwhile, an increase in the elongation of this alloy from 4.31% to 8.23% (increase of 90.9%) was also achieved. More importantly, the high strength-plasticity (“double high”) Al-Cu-Mg alloy was attributed to a cobweb-like sub-grain structure, which was proposed for the first time by utilizing reverse thinking to enhance plasticity through elevating dislocations, due to the formation of high-density dislocations from high-strain-rate rolling and rearrangement effect of dislocations from cryogenic treatment. Furthermore, the strength-plasticity mechanism was verified using in-situ tensile electron back scatter diffraction (EBSD), molecular dynamics (MD) simulations, and crystal plasticity (CP) models. The results indicated that the cobweb-like sub-grain structure, resembling countless walls, formed barriers that hindered dislocation migration towards high-angle grain boundaries (HAGBs) and absorbed them, thereby reducing the occurrence of stress concentration zones, i.e., the dislocation absorption and stress-strain sharing mechanisms. Additionally, the strengthening mechanism was associated with synergistic strengthening by multiscale microstructures, including micron-sized grains, micron-sized high-density dislocation lattices, and nanosized Al2CuMg phases, which were activated by successive deformation processes. Consequently, the concept of biomimetic structure design, which may serve as an effective method for achieving structural materials with high strength-plasticity synergy, can be extended to transportation fields, such as railway tracks and body structure design.

Effect of cementitious capillary crystalline waterproof material on the mechanical behavior of concrete

Cementitious capillary crystalline waterproof material (CCCW) is a material that can react with substances inside the concrete, generating crystals that fill the pores and cracks in the concrete. This chemical reaction is expected to improve the mechanical properties of the concrete. This study investigated the effects of CCCW content and water-cement ratio (W/C) on the compressive behavior of cementitious capillary crystalline waterproof concrete (CCCWC). The results indicated that as the CCCW content increased from 0% to 1.5% for W/C of 0.4, the compressive and tensile strength values of concrete slightly decreased. This is because excessive CCCW generates too many crystals within the concrete, leading to internal matrix expansion and crack formations. However, in the cases of W/C of 0.45 and 0.5, the compressive and tensile strength values of the CCCWC increased wit increasing CCCW content from 0% to 0.5%, but declined with 1.5% CCCWC addition. The reaction between CCCW and concrete generates numerous crystals, which densify the concrete matrix and enhance its strength. Moreover, with increasing W/C, the CCCWC's compressive strength and tensile strength decreased due to the increased porosity of the concrete matrix and the reduced availability of the concrete constituents that react with CCCW. Furthermore, the appropriate choice of CCCW content and W/C can significantly enhance the slope and peak stress of the stress-strain curve. Based on this, a compressive constitutive model of CCCWC was established. The findings showed that the optimal CCCW content varied with W/C. For instance, for a W/C of 0.4, the maximun compressive strength of 54.82 MPa was achieved without any CCCW addition. In contrast, the addition of 0.5% CCCW to concrete produced with W/C of 0.45 and 0.5 resulted in the highest compressive strengths of 50.98 MPa and 44.90 MPa, respectively.

Development of Fe-Cr-C alloys with high Mn content for bone implant

The object of this study is to combine the properties of Mn and the advantages of Fe-Cr-C to improve biomaterial compatible characteristics. Three alloys of Fe-Cr-C with compositions of 12 wt. % Mn, 16 wt. % Mn, and 20 wt. % Mn, were investigated. Microstructural analysis was carried out using a scanning electron microscope (SEM), and a Vickers hardness test kit was used to evaluate the hardness. The pin-on-disc method was used for the dry slide wear test, and the corrosion test was carried out using the three-electrode cell polarization method. The hardness value of Fe-Cr-C alloy increased by 28.7 % with the increase of Mn content from 12 wt. % (231.8 VHN) to 20 wt. % (298.4 VHN). The tensile strength value increased by 30.3 % with an increase in Mn content from 12 wt. % (522.69 MPa) to 20 wt. % (680.89 MPa), while the strain value decreased by 30.9 %. However, impact toughness did somewhat decline, from 0.213 J/mm2 at 12 wt. % Mn to 0.169 J/mm2 at 20 wt. % Mn. The wear rate results for Fe-Cr-C 20 wt. % Mn 0.000156 mm3/kg. show a reduction of more than 15 wt. % when compared to Fe-Cr-C 12 wt. % Mn because of an increase in the hard-intermetallic area. Additionally, corrosion resistance improved significantly, with the corrosion rate decreasing from 0.005814 mm/yr at 12 wt. % Mn to 0.001780 mm/yr at 20 wt. % Mn, demonstrating that higher Mn content reduces material degradation in corrosive environments. Based on the experimental results, Fe-Cr-C 20 wt % Mn alloy has the highest mechanical and corrosion resistance of the three types of alloys. Fe-Cr-C with high Mn alloys are promising candidates for application as biomaterials for bone implants by optimizing the Mn content and corrosion resistance

Characterization of Mixtures Based on High-Density Polyethylene and Plasticized Starch.

This paper presents the obtaining and characterization of blends based on high-density polyethylene (HDPE) and plasticized starch. In addition to plasticized starch (28.8% w/w), the compositions made also contained other ingredients, such as polyethylene-graft-maleic anhydride as a compatibilizer, ethylene propylene terpolymer elastomer, cross-linking agents, and nanoclay. Plasticized starch contains 68.6% w/w potato starch, 29.4% w/w glycerin, and 2% w/w anhydrous citric acid. Blends based on HDPE and plasticized starch were made in a Brabender Plasti-Corder internal mixer at 160 °C, and plates for testing were obtained using the compression method. Thermal analyses indicate an increase in the crystallization degree of the HDPE after the addition of plasticized starch. SEM micrographs indicate that blends are compatibilized, with the plasticized starch being well dispersed as droplets in the HDPE matrix. Samples show high hardness values (62-65° ShD), good tensile strength values (14.88-17.02 N/mm2), and Charpy impact strength values (1.08-2.27 kJ/m2 on notched samples, and 7.96-20.29 kJ/m2 on unnotched samples). After 72 h of water immersion at room temperature, mixtures containing a compatibilizer had a mass variation below 1% and water absorption values below 1.7%. Upon increasing the water immersion temperature to 80 °C, the sample without the compatibilizer showed a mass reduction of -2.23%, indicating the dissolution of the plasticized starch in the water. The samples containing the compatibilizer had a mass variation of max 8.33% and a water absorption of max 5.02%. After toluene immersion for 72 h at room temperature, mass variation was below 8%.

Influence of Density of 3D Printing Using the Fdm Method on Productivity and Mechanical Properties of ABS

The economic and technical advantages of 3D printing make it a possible replacement for conventional production processes, especially for complex products and small batches. It is important to point out that technological parameters of 3D printing, such as layer thickness, print density, print speed, melting temperature, and table temperature, have a significant impact on the mechanical properties and productivity of parts obtained by 3D printing. Because of all the above, there is a great interest in research in this area. The paper presents the results of testing the tensile strength of the ABS polymer, in which two parameters were varied: the thickness of the print layer (0.39 mm) and the print density of 60–100% in steps of 10% each. The samples were obtained on a ZORTRAX M200+ 3D printer using fused filament deposition (FDM) technology. The selected thickness of the printing layer is relatively large, and with it, parts with lower accuracy and high surface roughness are obtained, although at the same time high productivity is achieved, which can satisfy some requirements. The obtained tensile strength values show that increasing the print density leads to an increase in its value, with a deviation in the sample with a print density of 100%, whereas the tensile strength values are comparable to the values obtained by other authors.

Evaluation of the use and performance of natural filler based polypropylene/leonardite composites

The use of polypropylene (PP), which has reached a considerably high level in the last century and is one of the polymers whose properties have been investigated and studied in much more detail with the use of various additives, can be obtained as composite structures with the use of both inorganic and organic additives, and the desired properties can be modified according to the desired purpose. In this study, it was aimed to evaluate the behavior of leonardite, a rich source of humic acid, with PP composite structures, whose performance with thermoplastic materials has never been investigated before, although there are studies on its use in different sectors. To evaluate the effects of different ratios of leonardite additives on PP polymer, the composites were prepared with a twin screw extruder, and the test specimens were produced using an injection molding device. Spectroscopic, density, microscopic, mechanical (tensile, impact, flexural), thermal and color analyses of composites containing leonardite at 0, 0.5, 1, 3, 5, and 10 wt% were carried out. As the amount of leonardite in the composite increased, a slight increase was observed in the density values of the composites, with a maximum of 4.7%. In microstructure analysis, a homogeneous distribution of the filler was observed in composites reinforced up to 1 wt%, while agglomeration occurred at higher rates. While the highest tensile strength and flexural strength values were found for the 5 wt% leonardite filled composite, it was observed that these values increased from 31.8 MPa to 32.7 MPa and from 32.84 MPa to 37.84 MPa compared to the pure PP, respectively. The highest Izod impact strength value was determined for the 10 wt% leonardite filled composite and an increase in this value was obtained from 2.47 kJ/m2 to 2.85 kJ/m2. The nucleation effect explains the decrease in supercooling temperature observed in the thermal analysis results. Furthermore, an increase of the thermal stability of PP/leonardite composite structures was demonstrated. When the color analysis results were examined, it was seen that the leonardite additive caused the color of the composite to darken, as expected.

Study on Mechanical Properties and Fatigue of Cold-rolled Steel Plate for Distribution Transformer

The oil tank steel plate of the distribution transformer is covered with welds, and the fatigue failure of the oil tank often occurs in the internal defects of fillet welds. Given the above problems, this paper puts forward the bearing capacity calculation formula of cold-rolled steel plate and carries on the force analysis of steel plate and the fatigue analysis of weld through finite elements. Based on the theory of plastic limit design, the ultimate flexural bearing capacity of the control section of steel plate members is proposed. The calculation formula of equivalent structural stress is given based on the calculation method of structural stress and linear elastic fracture mechanics, and the calculation method of fatigue life and fatigue cumulative damage is given. Then, the elastic-plastic equation is solved according to three criteria: Mises yield criterion, plastic flow criterion, and strengthening criterion. Based on the above numerical simulation analysis, the mechanical model of steel plate weld is constructed, the mesh is divided, the boundary conditions are restricted and the same load is applied. ABAQUS analysis results show that the stress distribution curve of the connector has a maximum value at X = 80 mm and X = 210 mm, that is, the top surface of the connector steel plate has an obvious stress concentration at 80 mm and 210 mm. When the length of the weld is not more than 60 times the size of the welding foot, the full section of the core plate will yield, and the maximum stress value of the weld element will not exceed the tensile strength value of the welding material. The error of the results calculated by the formula in this paper is mostly within 10%, and the rest is basically within 20%. Therefore, the bearing capacity formula of the steel plate in this paper has ideal calculation accuracy and can provide effective guidance for the design of distribution transformer oil tanks.

Comparison of mechanical and flammability properties of thermoplastic and thermoset matrix glass fibre woven fabric composites

This study aims to examine the mechanical and burning properties of composites made from twill (0°/0° and 0°/90° orientations) and plain fabrics using hybrid yarns produced by combining glass and polypropylene yarns with interwoven and intermingled methods. The properties of interwoven and intermingled hybrid fabric composites were compared with thermoset composites. Each composite (56% glass fibre content) plate is produced by combining eight fabrics with the same parameters using the press moulding technique. The effects of yarn and fabric weaving types on the results were examined in detail. When the results are examined, the breakage of glass fibres in intermingled hybrid yarns negatively affects the strength results. Therefore, composites made with intermingled hybrid yarn types and plain weave types of fabric had the lowest tensile strength value (132 MPa). The composite of twill woven fabrics produced with interwoven yarns arranged in 0°/0° orientation had the highest tensile strength of 315 MPa, and these results were very close to those of thermoset composites. Although the 0°/90° oriented twill composite showed a 2.3 times lower tensile strength value than the 0°/0° oriented twill composite, it had a 7.7 times higher value when bending strength values were taken into account. The main reason for this is that glass fibres contribute to the warp and weft directions. It has been observed that the composite consisting of plain fabrics woven with commingled hybrid yarns had the highest impact resistance. Additionally, when the combustion results were examined, it was concluded that the type of yarn and fabric weaving affected the burning rate. The slower combustion of hybrid commingled yarn composites resulted from fibreglass breakage during yarn production. These findings provide valuable insights into optimizing composite materials for specific applications, considering factors such as weaving pattern, fibre orientation, and mechanical performance.

Mechanical properties of aramid and UHMWPE thermoplastic composites: numerical and experimental trials

The out-of-plane behaviour of 8 different composites exposed to very high deformation rates and non-standard conditions was investigated in our previous studies. The mechanical properties of these composites have been evaluated through tests conducted at deformation rates comparable to those experienced during explosions. Based on the relevant test results, this study conducted a numerical analysis of 3 best-performing Aramid UD GS3000, Artec Aramid/Woven Aramid CT736, and H62 UD-UHMWPE-reinforced composites. In this regard, LS-DYNA's MAT54 model was compared with other failure mechanics-based models and preferred because it requires less experimental data and can simulate damage progression in dynamic failures. Since the samples used in the study were non-standard, quasi-static tensile and shear tests were performed based on the loads to which the composites would be exposed to create an accurate numerical analysis. Both tensile and shear strength values of the Artec Aramid/Woven Aramid CT736 composite are higher than those of the Aramid UD GS3000 and H62 UD-UHMWPE composites. When the numerical analysis results were compared with the tensile test data, compliance rates of 99.84% for Aramid UD GS3000 reinforced composite, 99.34% for Artec Aramid/Woven Aramid CT736 reinforced composite, and 96.42% for H62 UD-UHMWPE reinforced composite were determined. The analysis showed that the shear stress-strain curves provided 100% agreement at the maximum stress value.

Grafting of Lactic Acid and ε-Caprolactone onto Alpha-Cellulose and Sugarcane Bagasse Cellulose: Evaluation of Mechanical Properties in Polylactic Acid Composites.

In this paper, we present the synthesis of composite materials comprised of α-cellulose and sugarcane bagasse cellulose fibers grafted with lactic acid and ε-caprolactone. These fibers were incorporated as reinforcements into a PLA matrix by extrusion, producing composite materials with improved mechanical properties. The grafting of lactic acid and ε-caprolactone onto the fibers was confirmed by FTIR spectroscopy, demonstrating the chemical modification of the fibers. The morphology of the fibers and composites was analyzed through scanning electron microscopy (SEM), showing that the fibers are encapsulated within the polymeric matrix. This suggests good PLA-fiber interaction for the 90 PLA/10 α-Cel, 90 PLA/10 LAC-g-α-Cel, and 90 PLA/10 ε-CL-g-α-Cel composite materials. The obtained composite materials were tested under tensile loading. Incorporating 10 wt% of LAC-g-FBA-Cel and α-Cel-g-FBA-Cel grafted fibers into the PLA matrix improved the tensile modulus by 28% and 12%, respectively, compared with PLA. The maximum tensile strength values obtained were for composite materials with 10 wt% PLA/α-Cel, LAC-g-α-Cel, and FBA-Cel with 23, 27, and 37% concerning PLA. DSC thermal studies showed a reduction in the glass transition temperature in the composites with grafted fibers. The results suggest better interfacial adhesion between the PLA matrix and both grafted and non-grafted α-cellulose fibers, which contributes to the observed improvements in the mechanical and thermal properties of the composite materials. The results demonstrate that the composites can be produced through extrusion. Once the optimal concentration has been determined, α-cellulose or sugarcane bagasse grafted with lactic acid and ε-caprolactone can be incorporated into the PLA matrix, exhibiting adjustable properties.

Sustainable concrete production: Partial aggregate replacement with electric arc furnace slag

Abstract The pursuit of sustainability in the construction industry has stimulated interest in seeking environmentally friendly alternatives to natural aggregates in concrete production. This study evaluates the behavior of concrete when electric arc furnace (EAF) slag is used as aggregates in its production. The primary research gap filled by this study is to deduce the blend of the fine and coarse EAF slag aggregates that would produce concrete of comparative strengths to concrete made with natural aggregates. Concrete mixtures were formulated using varied EAF slag content in the proportions of 0, 10, 15, 25, and 50%, respectively. The compressive strength values increased as the EAF slag content increased. However, this trend was not evident for the density and tensile strength values. The concrete mixture containing 25% EAF slag with 15% fine and 20% coarse EAF slag aggregates had the greatest density value of 2550.00 kg/m3 and the tensile strength value of 4.8 Pa respectively. This could be due to the distribution of the fine and coarse aggregate grains in the mixture. Since the percentage of fine and coarse aggregate grains were 10 and 15%, respectively, it was a close enough range for the fines to fill in the void spaces. This made the mixture more compact which resulted in a higher density and tensile strength values.

The Effect of Reinforcement Weight Ratios on the Mechanical Properties of ZrO2/ Unsaturated Polyester Nanocomposites

This work aims to prepare ZrO2/ unsaturated polyester nanocomposites with reinforcement weight percentage ratios (1, 2, 3, 4, 5, and 6) wt.% and study the effect of this reinforcement weight ratio on some mechanical properties such as hardness, impact strength, and tensile strength. The used powder has a monoclinic structure, P2/m space group, and unit cell parameters a, b, and c = 5.313Å, 5.210 Å, and 5.145 Å, receptively, and angels α, γ = 90º and β= 99.233º according to XRD data and using Dicvol 91 indexing program. The grain size of the used powder was estimated using Scherrer’s equation to be 43.2 nm. The SEM micrograph of ZrO2 nanopowder showed the particle morphology having homogenous irregular grains and appears to be similar to a coral shape. The results of the hardness test showed that increasing the reinforcement weight ratio led to an increase in the hardness values. Impact, tensile, and flexural strength values increase with the reinforcement weight ratio and peaked at 6 wt. %, and decreased at a higher ratio.