Band 33, Heft 1

This study evaluated the mechanical properties of the scrimber wood produced from date palm fronds and compared it to other wood-based materials. The raw materials for the production of the scrimber wood were date palm fronds. The scrimber wood was produced using a fabrication process that included the following stages: washing, cutting, burning, and gluing the pieces. The results showed that the mechanical properties of the scrimber wood produced using date palm fronds were very similar to those of other woods used for the same purpose. It was found that the wood produced was strong enough to hold several heavy objects without deforming or breaking. In addition, no defects, such as cracks or holes, were observed on the surface of the wood after processing. The results revealed that frond-scrimber trees recorded the largest deflection before fracture due to their fibrous features. The fibrous structure of the frond scrim may explain its strength and durability, as it successfully supplied samples with high fracture points, similar to hardwood, and prolonged maximum displacement, similar to certain softwoods. The dynamic characterization of the scrimber wood specimens reveals their inherent frequencies, mode forms, damping ratios, and other dynamic properties; such insights may help forecast their performance under different loads.

The study focused on examining the behavior of six concrete beams that were reinforced with glass fiber-reinforced polymer (GFRP) bars to evaluate their performance in terms of their load-carrying capacity, deflection, and other mechanical properties. The experimental investigation would provide insights into the feasibility and effectiveness of GFRP bars as an alternative to traditional reinforcement materials like steel bars in concrete structures. The GFRP bars were used in both the longitudinal and transverse directions. Each beam in the study shared the following specifications: an overall length of 2,400 mm, a clear span of 2,100 mm, and a rectangular cross-section measuring 300 mm in width and 250 mm in depth. To apply loads for testing, two-point static loads were placed at the middle third of the beam’s span, creating a shear span of 700 mm in length. The beams were categorized into three groups depending on the GFRP longitudinal reinforcement ratio in the tension and compression zones of the section. GFRP bars with a diameter of 15 mm were employed as longitudinal reinforcement, while closed GFRP stirrups with a diameter of 8 mm at 100 mm were utilized as transverse reinforcement throughout the structural element. Test results have indicated that the ultimate load capacity of doubly GFRP-reinforced concrete beams varies compared to singly GFRP-reinforced beams. The range of variation observed is between an increase of 8% and a decrease of 4%. Accordingly, the contribution of the GFRP bars in the compression zone is insignificant and could be ignored in design calculations. It was observed that the loading level at which crack spacing stabilized ranged between 31.3 and 87% of the experimental failure load. It seems that the crack spacing decreased with the increase in the reinforcement ratio.

The objective of this study is to explore the feasibility of developing environmentally friendly green roller-compacted concrete (RCC) by utilizing locally available materials. The research investigates the behavior of RCC properties when different amounts of solid waste materials (brick powder, glass powder, and steel slag) are added as substitutes for cement content. To accomplish this, four laboratory tests were conducted: compressive strength, flexural strength, X-ray diffraction analysis, and scanning electron microscope imaging. These tests aimed to identify the changes in concrete properties resulting from the inclusion of waste construction materials as cement replacements. The study employed an approach that involved adding waste materials to the concrete mixture, with replacement percentages ranging from 10.0 to 40.0% in increments of 10.0%. Consequently, 12 concrete mixtures were prepared to examine the effects of adding waste materials (10.0–40.0%) as substitutes for cement content. In addition, one reference mixture was designed without any inclusion of waste materials for comparison purposes. In general, the results indicate that as the percentage of waste construction materials increases in the mixtures, there is a corresponding decrease in compressive strength. However, it is noteworthy that the strength activity index (SAI) exceeded 75% according to ASTM C618 standards. This indicates that the waste construction materials possess pozzolanic properties, making them suitable for use as cement replacements in RCC mixtures.

Fiber-reinforced plastic (FRP) is utilized in the fabrication of the primary structures of FRP boats. A majority of these structures are produced using molds. Subsequently, these products often experience deformation upon being released from the mold, as well as when they are exposed to high temperatures. Hence, it is crucial to carry out experimental investigations and evaluations related to the deformation of laminated composite structures. The specimens, which are in the form of L-shapes and curve-shapes, are constructed using unsaturated polyester resin and fiberglass material. The study focuses on two independent variables, namely the percentage of hardeners and the temperature during the manufacturing process. The output factor under examination is deformation, which is measured on these specimens. Subsequently, all of the specimens are subjected to varying levels of temperature using an oven as the working condition. The deformation is further assessed based on the experimental findings and regression equation. The results indicate that as the rate of hardener and temperature increase, the level of deformation decreases. Additionally, it was observed that when the temperature rises from 500 to 800°C, the specimens with initial deformation values that are either too high or too low undergo rapid changes. Moreover, the experimental equations can be utilized to predict the values of deformation or input factors.

The aim of this research is to investigate whether construction rubbles may be utilized as coarse aggregates in concrete. Experimentally, the slump, unit weight, compressive, tensile, and flexural strength tests were applied on concrete samples with varying percentages of recycled coarse aggregate (RCA) and compared with reference concrete produced with natural coarse aggregate. This research conducted 96 concrete samples with RCA replacement percentages of 0, 35, 65, and 100%, respectively. The control mixture produced with natural aggregate showed better results than the mixtures containing recycled aggregate; thus, compressive, tensile, and flexural strengths reduced as the amount of the recycled aggregate increased. Using 100% RCA, the compressive, tensile, and flexural strength reduction reached up to 64, 29, and 38%, respectively.

Glass- fiber-reinforced polymer (GFRP) offers a significant alternative to steel in reinforced concrete, with superior corrosion and fire resistance. Though less ductile and more brittle in stress–strain behavior than steel, it is very helpful to combine GFRP with steel reinforcement that improves the structural behavior. This research investigates the flexural characteristics of a one-way slab reinforced by a combination of GFRP and steel reinforcement. Three identical concrete slabs ((1500 × 550 × 120) mm and 43 MPa) were tested under static load with GFRP replacement ratios of (0, 20, and 40)%. The experimental data were utilized to verify a numerical model. The experimental outcomes indicated a substantial impact of the GFRP replacement ratio on the failure mode. The failure mode was flexural, flexural-shear, and shear regarding the reference slab, 20%, and 40% replacement, respectively. GFRP replacement influenced ductility and ultimate load by (9.13 and 10.7)% and (−21 and 5.0)% for replacement ratio (20 and 40)%, respectively. Based on the numerical analysis, the parametric study (considerably affected the structural response. Failure mode changed to flexural, and shear-flexural concerning (20 and 40)%, respectively. The optimum load was characterized at 40%, while max toughness and ductility were achieved at 20%.

In this research, we were interested in studying whether vetiver fibers (VFs) treated with different concentrations of sodium hydroxide (NaOH) affect the mechanical properties of VF and epoxy resin (ER) composite material in a better way. As part of the experiment, VFs were treated with NaOH in various concentrations ranging from 0.5, 1, 1.5, 2, 2.5, and 3 mol/L. All of them were molded into composite material in the ratio of 10 wt% with ER. After that, they were tested for mechanical properties such as the tensile strength, impact strength, bending strength, and compressive strength to find the best mechanical properties. In addition, the surface was investigated with scanning electron microscopy (SEM) for adhesion of the VFs with ER. The results of the experiment were not as expected. We found that, increasing the concentration of vetiver treated with sodium hydroxide resulted in a decrease in the mechanical properties of the composite. The best values for impact, tensile, bending, and compressive strengths were 256.42 kJ/m 2 , 38.45 MPa, 43.70 MPa, and 110.27 MPa, respectively, and 0.5 mol/L is the best concentration of NaOH for mechanical strengths of the composites. Moreover, from SEM technique, it was found that the mechanical properties decreased at higher concentrations. This may be caused by damage to the VFs due to excessive NaOH corrosion and this point should be taken for further study.

Herein, fatigue and crack propagation tests were conducted using the small-punch-fatigue (SPF) test to verify its applicability to assess fatigue strength and fatigue crack propagation behavior. During the SPF test, a fatigue crack first initiated at the specimen center and then propagated in the radial direction. In most cases, three fatigue cracks propagated from the specimen center to the radial direction in point symmetry. X-ray computed tomography revealed that the crack initiated by the SPF test had a quarter ellipse shape. Elastic finite element (FE) analysis was conducted to estimate the stress state and stress intensity factor (SIF) of the specimen, and an approximate equation was obtained as a function of the applied load. The experimental results comprising fatigue lives and crack growth rates obtained via the SPF test were compared with the conventional uniaxial test data as functions of the stress amplitude and SIF determined via elastic FE analysis, respectively. This comparison showed that the SPF test can be applied to the fatigue test and fatigue crack propagation test.

Magnetorheological elastomers (MREs) are intelligent materials that exhibit changes in their properties when exposed to a magnetic field. By applying a magnetic field during the curing process, MRE can be made anisotropic. This study focuses on optimizing the fabrication process parameters using the design of an experimental approach, namely the Taguchi method. The parameters to be optimized for MRE fabrication include the number of coil turns, coil diameter, curing current, and curing time. Twenty-five sets of anisotropic MRE were fabricated and subjected to drop impact testing to evaluate their impact absorption capability. The results were further examined for a more comprehensive analysis using the signal-to-noise ratio, analysis of means, and analysis of variance. This rigorous examination aimed to pinpoint the optimal parameters and the key factors influencing the fabrication of the MRE. From the analysis result, it can be seen that the number of coil turns contributed to 63.36% of the entire MRE fabrication process. Furthermore, a well-defined composition for the MRE was identified, consisting of 200 coil turns, a coil diameter of 1.0 mm, an applied current of 1.2 A, and a curing time of 20 min.

Recently, rainfall-induced slope failure has struck Cimanggung village, West Java province, Indonesia. In order to anticipate future slope failures due to rainfall, an unsaturated slope stability analysis is compulsory. Precise information on the soil–water characteristic curve (SWCC) is required to conduct an accurate unsaturated soil analysis. In this article, a procedure to obtain SWCC by using a polymer tensiometer for Cimanggung village is proposed. Considering the long period of time needed to obtain the measured data, some prediction methods are available. The measured SWCCs are then compared with SWCCs based on two prediction methods. Chin’s 1-point and Perera et al. ’s methods are applied as the prediction methods and then compared with the measured SWCCs. It could be concluded that Chin’s 1-point method yields a close estimation within the suction range. Meanwhile, the Perera et al. method underestimates the air entry value, and the predicted curve deviates significantly with the measured SWCC. Hence, Chin’s 1-point method is recommended for predicting SWCCs in Cimanggung Village.

This research examines the impact of using hybrid nano-sustainable materials such as nano-silica and nano-slag, at three designated contents (2, 4, and 6%) by the cement weight. Mechanical and physical characteristics were studied at 7 and 28 ages. Overall, the experimental results showed the positive impacts of used hybrid nano-sustainable additives on fresh and hardened properties of modified cement mortar. The compressive strength of mortar containing nano-slag with 2, 4, and 6% enhanced as 11, 33, and 32% at 28 days, respectively, and correspondingly, direct tensile strength enhanced as 16, 39, and 30% at 28 days, respectively. Furthermore, the compressive strength of cement mortar containing 2, 4, and 6% of nano-silica improved by 20, 44, and 59% at 28 days, respectively. Besides direct tensile strength improved by 19, 37, and 46% at 28 days, respectively, as compared with reference cement mortar. The 4% nano-slag and the 6% nano-silica showed the optimum results of improvements of the compressive strength and direct tensile strength as 33 and 39% and 59 and 46% at 28 days, respectively. Hence, the optimization results of selected cement mortar comprising hybrid nano-sustainable materials as 6 wt% nano-silica and 4 wt% nano-slag produce a greater enhancement of mortar strength. Compressive and direct tensile strength improved by 73 and 53% at 28 days, respectively.

This experimental study examines the effect of a novel severe multiaxial loading path on the plastic buckling of copper (CuTWC) and aluminum (AlTWC) thin-walled tubular structures to improve their energy-dissipating capacity. The study presents a new variant of the patented compression-torsion rig (ACTP) in the alternating mode for the torsion component, called ACTP-S. This variant increases the loading complexity, resulting in enhanced energy absorption. The component’s loading complexities range from moderate mode to severe biaxial mode, tested under quasi-static (5 mm/min) and dynamic (9 m/s) regimes, thanks to its S-shaped helices. After analyzing the results, it is clear that the strength of the tested structures increased with greater load complexity for both regimes. Additionally, each system exhibited a higher energy absorption capacity. For example, the CuTWC and AlTWC experienced a 47 and 91% increase, respectively, under the most severe biaxial mode compared to the reference tube, which was tested under uniaxial loading. This demonstrates the effectiveness of the new ACTP-S device, considering the specific sensitivity of each material to the loading path complexity.

The incorporation of frequency vibration into the powder mixed electric discharge machining (PMEDM) process has the potential to significantly enhance the productivity and quality of the machining process, as well as to provide a great deal of opportunities in this sector. An analysis and evaluation of the machining productivity (material removal rate [MRR]) in PMEDM with low-frequency vibration was carried out in this work by considering SKD61 as a workpiece. The oil dielectric solution mixed with titanium powder was used as a dielectric medium with red copper (Cu) as the electrode. At this point in time, the process technology parameters that have been chosen for inquiry are as follows: current ( I ), pulse on time ( T on ), powder concentration ( C p ), P , F , and A . The Taguchi technique (L 25 ) was used to create the experimental matrix. With the use of analysis of variance, it was able to examine the impact that the factors had on MRR, and the analysis was utilized to ascertain the highest possible value of MRR. I was the parameter that has the most significant effect, according to the findings, whereas T on was the parameter that has the least significant effect. The maximum value of the MRRmax is equal to 31.29 mm 3 /min.

Mirror epoxy, used in its pure form with a resin-to-hardener ratio of 100:50, is emerging as an innovative material widely used in modern flooring. Its appeal lies in its smooth, shiny surface, offering a unique and contemporary aesthetic. However, understanding its long-term viscoelastic behavior is essential to ensure the durability and performance of floor coverings under various conditions of use. This study examines the evolution of the Schapery model for mirror epoxy, focusing on its long-term viscoelastic behavior. Creep tests at constant loads and ambient temperature are carried out in order to numerically determine the static nonlinearity factors g and g 0 formulated in the Schapery model. To validate this model, other relaxation tests at constant deformations are carried out under the same conditions, which allowed us to determine the nonlinearity factors h and h 0 formulated in this model using the same method. A remarkable consistency between the variations in the experimental and numerical values of the model programmed on MATLAB allows us to conclude that the Schapery model describes the real behavior of the mirror epoxy in a satisfactory manner.

Ballast structures continue to be utilized in Indonesia’s railway system. They are essential for conventional railway lines, which experience high levels of stress and are susceptible to damage from train traffic. This study examined the utilization of a pressure test machine and sieve analysis to determine the abrasion value of ballast made of 60/70 penetration asphalt with a binder and stabilizer material consisting of a mixture of latex and roving fiber. The test results revealed that the compressive strength of the ballast structure was positively affected by the addition of asphalt, latex, and roving fiber. However, when comparing the compressive strengths of the two ballast structures, the ballast structure with 2% asphalt and 3% latex generated superior results to that with 4% asphalt and 1% latex. In other words, asphalt, as opposed to latex, was more effective in protecting ballast material from abrasion.

Natural sources used in industry, such as environmental waste fibers for plants, waste paper, and others, can lessen waste-throwing problems and reduce environmental pollution to save lives on the earth’s crust. The natural composites of natural fiber-reinforced thermoplastic are undoubtedly to be sustainable and eco-friendly. Therefore, the current work was conducted to study the addition of natural fiber date palm Khestawi-type fiber (DPKF) with different loadings (5, 10, and 15%) into the polypropylene (PP) matrix to prepare DPKF/PP composites. The specimens were prepared by using the lamination method. In addition, the mechanical properties of these composite material specimens were studied by following ASTM, which included tensile, flexural, and impact tests. A scanning electron microscope (SEM) and X-ray diffraction (XRD) were employed to analyze the morphology and the structure crystallite studied of the DPKF/PP composites. The results show that the DPKF/PP composite with 15% fiber content recorded the best tensile strength, tensile modulus, and low tensile strain performance. Moreover, XRD and SEM analysis confirmed the mechanical properties and crystalline nature of the DPKF/PP composites. Finally, the values of the flexural and impact properties increased with increasing fiber loading.

The mechanical behavior of the tin (Sn)–silver (Ag)–copper (Cu) (SAC) lead-free solders is strongly influenced by the isothermal aging due to the evolution of the microstructure and mechanical properties. This study aims to examine the influence of pre-isothermal aging at 100°C on the mechanical behavior of different SACN05 alloys with different silver content including N = 1 , 2 , 3 N=1,\hspace{.25em}2,\hspace{.25em}3 and 4% by applying nonlinear finite element analysis. The mechanical properties, including elastic and inelastic properties, of the SAC systems with various Ag percentages are gathered from the literature and incorporated in thorough thermomechanical simulations. In addition to the unaged solders condition, two aging periods, 6 and 12 months, are studied. The computational results showed that the mechanical response of pre-aged SACN05 solders is significantly influenced by the aging duration and silver content. Specifically, interconnects with higher Ag percentage are shown to be more resistive to aging and expected to have lower thermally induced inelastic deformations, strains, and strain energies. Therefore, better thermal fatigue performance and improved failure resistance is potentially expected. However, the pre-isothermally aged SACN05 solders generally exhibit lower resistance to the accumulations of inelastic strains and strain energies. Thus, it is probable that pre-aged SACN05 solders will demonstrate deterioration in thermal fatigue performance compared to unaged interconnects. Nonetheless, the aged SAC solder systems could be an innovative solution for designing electronic devices regularly exposed to shock and impact loading as the aging process significantly reduces the brittleness of the SnAgCu alloys.

In order to lessen carbon emissions, preserve natural resources, and enhance the planet’s sustainability for future generations, environmentally friendly and sustainable composites offer a promising solution that combines technological innovation and environmental responsibility. Therefore, the current study focused on the development of walnut shell (WS) powder as a natural reinforcing additive for polypropylene (PP) composites as sustainable materials for potential automotive applications. Different particle sizes (150, 212, and 300) μm and particle content (10, 20, 30, and 40 wt%) of WS-reinforced PP composites were investigated. This investigation involved two strategies: The first strategy was to determine the best WS size and loading in the PP matrix. The second strategy involved the development of additives by applying dual treatment methods on the WS: alkaline and microwave as chemical and physical treatment at the same time. Under fixation microwave conditions, different NaOH concentrations of 3, 5, and 7% were applied. The extrusion and hot compression processes at fixed operating conditions were used to combine all dosages of WS/PP composites. The mechanical properties of tensile, flexural, and impact for all the composite dosages for the strategies were studied according to ASTM standards D638, D790, and D256, respectively. To confirm the mechanical properties, the influence of treatment techniques on the WS powder and WS/PP composites was also investigated using physicochemical characterization Fourier transform infrared spectroscopy, scanning electron microscope, and X-ray diffraction. Furthermore, the best WS/PP composite was compared with the real automotive part (automobile steering airbag cover [ASAC]) to confirm the mechanical properties of the new WS/PP composites. The results showed that the first strategy obtained a 212 μm, 20 wt% composites that achieved the highest tensile strength, which increased about 1.2 times the tensile strength of the PP matrix. The second strategy showed composite that had treated WS with 7% NaOH (WS7Comp) attained the best mechanical properties throughout other WS/PP composites. In addition, the mechanical properties of the new WS/PP composites were adjusted to the ASAC mechanical properties. Therefore, the improved composites could be a promising alternative material for automotive applications.

This research investigates the mechanical behavior and performance of AH32 steel when subjected to low temperatures, particularly in the context of ship hull structures operating in cryogenic environments. The study uses experimental procedures and advanced numerical simulations through ABAQUS CAE to evaluate vital mechanical properties such as Young’s modulus, yield stress, ultimate tensile strength, and fracture toughness across temperatures ranging from 20 to −160°C. The results reveal a consistent trend of increasing strength and decreasing ductility at lower temperatures, with validation achieved through an error margin of less than 10%. The findings underscore the material’s suitability for cryogenic applications but highlight the potential for brittle fracture, necessitating careful design considerations in Arctic or liquefied natural gas transport conditions. However, the study is limited to specific geometric configurations and loading conditions, suggesting that future research should explore additional geometries, fatigue behavior, and long-term performance under varying environmental conditions to assess the material’s viability in extreme environments fully.

Machine learning’s prowess in extracting insights from data has significantly advanced fluid rheological behavior prediction. This machine-learning-based approach, adaptable and precise, is effective when the strategy is appropriately selected. However, a comprehensive review of machine learning applications for predicting fluid rheology across various fields is rare. This article aims to identify and overview effective machine learning strategies for analyzing and predicting fluid rheology. Covering flow curve identification, yield stress characterization, and viscosity prediction, it compares machine learning techniques in these areas. The study finds common objectives across fluid models: flow curve correlation, rheological behavior dependency on variables, soft sensor applications, and spatial–temporal analysis. It is noted that models for one type can often adapt to similar behaviors in other fluids, especially in the first two categories. Simpler algorithms, such as feedforward neural networks and support vector regression, are usually sufficient for cases with narrow range variability and small datasets. Advanced methods, like hybrid approaches combining metaheuristic optimization with machine learning, are suitable for complex scenarios with multiple variables and large datasets. The article also proposes a reproducibility checklist, ensuring consistent research outcomes. This review serves as a guide for future exploration in machine learning for fluid rheology prediction.

Piping systems in thermal power plants are generally subjected to creep–fatigue loading caused by internal pressure, bending moment, and torsional moment in a high-temperature environment. These loadings cause Type IV cracks to form in the heat-affected zone in the weldment of the piping. In this study, we attempt to predict the creep–fatigue Type IV crack initiation life using a wireless micro-electromechanical system-type gyro sensor to understand the damage progress in plant components for the establishment of digital twin technology, which has recently attracted attention. The strategy for developing the system is as follows: i) remotely and sequentially import signals from a sensor attached to the actual component to a personal computer and ii) identify mechanical conditions such as bending and torsional moments in the piping component even in a high-temperature environment. This study first shows how to identify both moments in a piping system based on the rotation angles (deflection and torsion angles) measured using a gyro sensor. Next, a creep–fatigue life diagram is constructed based on the equivalent bending moment, which can combine the two independent parameters of bending and torsional moments into a single parameter. Finally, creep–fatigue tests were performed on a P91 steel piping weldment specimen using the high-temperature bending–torsional creep–fatigue testing machine developed by our group, and it was shown that the equivalent bending moment identified from the gyro sensor attached to the piping specimen can predict the Type IV creep–fatigue crack initiation life at the weldment.

Multiaxial creep investigations at high temperatures are required to guarantee the integrity of structural materials such as boiler pipes for power generation and turbine blades for aviation and industrial applications. The multiaxial creep testing method using a cruciform specimen has several advantages, and the authors successfully downsized the specimen. The authors also developed a technique for the in situ observation of the specimen in an electric furnace and the non-contact displacement measurement in the development of a biaxial tensile creep testing machine for the miniature cruciform specimen. By observing the specimen at a target mark during the creep testing through an observation window installed at the bottom of the furnace, it was possible to visualize the specimen surface variations and obtain the axial strain from the locus of the target marks. The Mises-type equivalent strain was calculated from the axial strains obtained in the equi-biaxial tensile multiaxial creep testing and was compared with the strains obtained in the uniaxial creep testing. The Mises-type equivalent strain can be expressed using a unified method up to approximately 5% of the initial strain in the test, even in the multiaxial stress state.

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/m 3 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 emergence and progression of synthetic rubber have paved the way in variegated prospects across various engineering and technological fields. Nonetheless, its inherent limitations such as poor mechanical and thermal properties including wear resistance, poor tensile strength, and lower thermal conductivity, as evident in styrene butadiene rubber and silicone rubber, have constrained its utility in numerous load-bearing scenarios. This limitation has been addressed by incorporating specific nanofillers into various rubber compositions, resulting in promising outcomes up to a certain threshold. Many nanofillers were trialed, such as graphite oxide, aluminum oxide, carbon nanotubes, and boron nitride. However, an attempt should be made to explore the disparity in dimensional attributes of nanofillers and their effect on different properties of rubber, thereby delineating the scope for future research. The exploration of dimensionally distinct nanofillers, such as 1D multiwalled carbon nanotubes and 2D graphene, can overcome these limitations and augment rubber’s mechanical properties and thermal properties. The study also delineates the scope of future research, which should be focused on optimizing the nanofillers’ dispersion and interfacial bonding within the rubber matrix by trying dimensionally different nanofillers.

Comparing polymer matrix composites with conventional composites, such as continuous fiber-reinforced composites, shows a considerable increase in strength and fracture toughness. In this study, compression molding was used to create hybrid (carbon and silk fabric-reinforced) and carbon fabric-reinforced epoxy matrix composites using a hand layup process. This article discusses the evaluated flexural strength (FS) and plane strain Mode-I fracture toughness of composite materials. The impact of carbon fabric reinforcement on the fracture toughness of these composites was assessed using the obtained results. It was found that the addition of silk fabric reinforcement decreased the hybrid composite’s plane strain Mode-I fracture toughness. Fracture toughness and FS are higher in carbon fabric-reinforced composite than in hybrid composite.

Direct metal deposition (DMD) is a layer-by-layer material addition process. Partial functionally graded material (FGM) blocks of size 26 mm wide × 34 mm thick × 32 mm height were 3D printed based on Taguchi’s L9 approach using a commercial DMD machine equipped with a diode laser. The parameters selected for FGM deposition were laser power, scan velocity, and powder feed rate. The metal powders used for deposition were Stainless Steel 316L (SS316L) and Inconel 625 (IN625). The novelty is the introduction of three gradient layers for joining dissimilar materials of SS316L and IN625. ASTM E8 tensile specimens were cut from each FGM block for testing and characterization. Tensile test results revealed that the thick-layered partial FGM specimen-6 had a high ultimate tensile strength (UTS) of 532.6 MPa at the sixth set of optimum parameters. This is due to the mixed presence of coarser and fine columnar grains and equiaxed grain microstructures. Based on the analysis of variance, scan velocity had a more significant effect on UTS and powder feed rate on micro-hardness. However, a maximum micro-hardness of 202.5 HV was observed in the gradient layers of the ninth sample at the ninth set of parameters. The fractography analysis revealed the ductile failure of specimens.

This article aims to investigate the tensile properties of carbon fibre-reinforced plastic (CFRP) and self-reinforced polypropylene (SRPP) composites used in both experimental and numerical investigations. The experimental study evaluated the tensile strength, tensile strain, and modulus of CFRP and SRPP composite laminates under tensile loading. Finite element modelling was employed to predict and validate the tensile properties of these composites. CFRP and SRPP laminates were manufactured using the hot compression technique and stacked through the hand lay-up technique. The results revealed that CFRP with a unidirectional pattern provided a higher tensile strength (1,162 MPa) than the twill pattern (288 MPa) with nominal strain values of 0.017 and 0.013 in the CFRP-based system, respectively. It was observed that the results of CFRP and SRPP composites provided a good agreement between experimental and numerical investigations. Moreover, the failure behaviour of CFRP and SRPP laminates was evaluated and compared with experimental and numerical results. Furthermore, practical applications of CFRP and SRPP composites for lightweight parts are presented.

Research on plasma nitriding was carried out on M50NiL bearing steel, subject to temperatures ranging from 460 to 560°C over periods from 4 to 40 h, while keeping the gas mixture at a steady ratio of 80H 2 :20N 2 . To examine the phase structure and chemical composition of the plasma nitrided layer, techniques such as energy dispersive spectrometry (EDS) and X-ray diffraction (XRD) were utilized. The M50NiL steel sample heated to 550°C for 24 h was found to contain an unusually high amount of nitrogen, as per the EDS analysis. The majority of the nitrided layer’s composition is made up of nitrogen-expended phases. Following XRD analysis, several peaks were identified, including α′-FeN, γ′-FeN, γ′-Fe 3 N, α′-Fe, and γ′-Fe. The main objective of this research was to explore the impact of temperature on the microstructure, hardness, wear resistance, and corrosion resistance of the surface nitrided layers. The steel that underwent nitriding at 500°C for 4 h demonstrated a significantly higher surface hardness of 1,332 HV, with an additional increase in case depth by 62.00 μm. The findings suggest that both the duration and temperature of nitriding affect the depth of the plasma nitrided layer. The surface hardness of the plasma samples was found to be notably improved. The steel sample, PN 500, nitrided at 08 h, exhibited the highest wear resistance among the nitride samples. The wear resistance of the samples was shown to be significantly enhanced. Potentiodynamic tests were conducted to assess the corrosion resistance of the nitrided steel, revealing that it was notably more resistant than the untreated steel. Furthermore, it was observed that steel nitrided for shorter durations at lower temperatures ( e.g. , 460°C for 4 h) demonstrated superior corrosion resistance compared to samples nitrided at higher temperatures.