Mechanical Properties Of Materials Research Articles

The Investigation of Morphological and Mechanical Properties of Polymer-Based Electrospun Nanofiber Coated Polystyrene and Recycled Polyethylene Terephthalate Composite Materials

The Investigation of Morphological and Mechanical Properties of Polymer-Based Electrospun Nanofiber Coated Polystyrene and Recycled Polyethylene Terephthalate Composite Materials

Effect of Cell Size on the Mechanical Properties of the Porous Structure of a CuCrZr Alloy Formed by Selective Laser Melting Technology

The porous structure has been widely used in heat sinks in aerospace fields because of its good specific strengthand lightweight. The porous structure formed by selective laser melting technology offers many advantages, but it also presents some challenges, for instance, how to how to ensure that the density is greatly reduced without sacrificing the material's mechanical properties. The Schoen I‐graph‐wrapped package structure with different cell sizes under the same volume fraction had been designed and fabricated by selective laser melting technology using CuCrZr powder as the raw material. The microstructure, grain orientation, and static properties were explored. At the same volume fraction, the pores were almost completely blocked when the cell size was 2 mm, with reduced powder adhesion when the cell size was 9 mm. As the cell size decreases, the compressive strength increases, with the compressive strength reaching 180 MPa at a cell size of 2 mm. Moreover, the energy absorption efficiency increases with the increase in cell size, with the highest energy absorption efficiency of 28% at a cell size of 9 mm. The limit dimensions under these conditions were determined to provide a reference for related research in this field.

Optimal development and performance evaluation of electrolytic graphene oxide synergistic all-solid waste cementitious grouting material

The low-carbon and friendly alkali-activated cementitious (AACM) grouting material has a broad application potential in the field of grouting engineering due to its excellent workability and higher early strength and is expected to replace cement grouting material in the future. In this study, an AACM grouting material using electrolytic graphene oxide (EGO) synergistic ground granulated blast-furnace slag (GGBS)-fly ash (FA)-rice husk ash (RHA) solid waste was proposed. The optimal ratio was 0.025 % EGO, 8.13 % FA, 26.6 % RHA, and 65.27 % GGBS, which determined by the Analytic Hierarchy Process (AHP), Entropy Weight Method (EWP), and Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS) methods. A systematic evaluation of the mechanical properties and impermeability of the proposed AACM grouting material was conducted by macro experiments (compressive strength, flexural strength and permeability) and micro experiments (XRD, SEM-EDS, Fourier Transform Infrared Spectrometer (FTIR) and Thermogravimetry Analysis (TG)). The results show that the increment of compressive strength and flexural strength for AACM grouting material with 0.025 % EGO compared to the cement water-glass grouting material were 161.2 % and 2.9 %, respectively, at 7-day. While the permeability coefficient compared to AACM grouting material without EGO decreased by 43.9 %. The XRD results show that the EGO reduced the intensity of AACM grouting material diffraction peaks, and FTIR analysis reveals that EGO increased the visibility of O-C-O characteristic peaks. These confirmed that EGO could enhance the degree of alkali activation reaction. The TG results indicate that the addition of EGO promoted the formation of carbonates, which strengthen the mechanical properties of AACM grouting material. The SEM-EDS results demonstrate that EGO increased the Ca/Si ratio, promoted the formation of highly polymerized hydration products.

Synergistic effects of sisal/glass fiber hybridization and eggshell powder filler on the performance of eco‐friendly polymer composites

AbstractIn recent years, there has been a significant emphasis on the development of composite materials that are both high‐performing and environmentally friendly. Hybrid polymer composites that are reinforced by both sisal and glass fibers are introduced in this study. Investigation was conducted to evaluate the combined influence of hybrid reinforcements and Egg Shell Powder (ESP) on the mechanical properties of the composites. The hand layup technique was employed to create hybrid laminates by incorporating variable amounts of ESP (0–15 wt%) and employing various stacking sequences. Various mechanical testing was administered to the composites that had been prepared. The results indicated that the glass/sisal hybrid laminates exhibited superior mechanical properties in comparison to the non‐hybrid sisal laminates, which was attributed to the synergistic benefits of incorporating both sisal and glass fibers. The incorporation of Egg Shell Powder significantly improved the material's mechanical properties. The glass/sisal hybrid laminates with 15% ESP laminate demonstrated the maximum tensile strength (195.23 MPa), flexural strength (150.02 MPa), and ILSS (7.55 MPa). Scanning electron microscopy enabled a comprehensive analysis of the hybrid composites' interfacial adhesion and microstructure. This investigation verified that the ESP was effectively dispersed and had a substantial effect on the interface between the matrix and the fibers. The hybrid composites that are generated are environmentally friendly and exhibit extraordinary potential for a variety of applications, offering a sustainable and high‐performing alternative to conventional synthetic composites. These discoveries promote the utilization of bio‐based resources in the composites industry and advance the development of sustainable materials.Highlights The glass/sisal hybrid laminates with 15% ESP laminate showed highest tensile strength of 195.23 MPa Hybrid composites exhibited superior mechanical properties. ESP addition significantly improved interfacial adhesion and strength Water absorption decreased with increasing ESP content up to 15% Development of Eco‐friendly composites suitable for automotive and aerospace applications

Experimental Characterization of the Mechanical Properties of Filter Media in Solid–Liquid Filtration Processes

Nonwoven filter media are used in many industrial applications due to their high filtration efficiency and great variety of compositions and structures which can be produced by different processes. During filter operation in the separation process, the fluid flow exerts forces on the filter medium which leads to its deformation, and in extreme cases damage. In order to design or select a reliable filter medium for a given application, it is essential to have a comprehensive understanding of the mechanical properties of the nonwoven material. In general, the properties of the filter material are influenced by temperature and can be changed during loading due to irreversible deformation, fatigue, and aging processes. In order to gain a deeper comprehension, the presented study examines the influence of temperature and repeated tensile stress on the filter medium properties. The focus is on fuel and oil filters employed in automotive applications. The characteristic properties of the samples, including thickness, porosity, and permeability as well as Young’s modulus and Poisson’s number, are measured. Young’s modulus is determined for both new and aged samples. In addition, the viscoelastic behavior is investigated via a dynamic mechanical thermal analysis. The results demonstrate a significant dependence of mechanical properties on the material composition and the aging effects.

Effect of fly ash chemical components on epoxy mortar composite material performance

This study focuses on the application of fly ash (FA)-filled epoxy mortar composite material (EMCM) as a bed material for precision machine tools, emphasizing the impact of fly ash’s primary chemical components (SiO2, Al2O3, Fe2O3, and CaO) as mono-component or two-component fillers on the mechanical properties of EMCM composite material. The research thoroughly analyzed the porosity, macroscopic mechanical properties, and microstructure of the EMCM. The results revealed that increasing the filler content up to 40% significantly enhances the elastic modulus and compressive strength of the EMCM specimens, despite an increase in porosity. Specific filler combinations, such as SiO2/CaO and CaO/Fe2O3, exhibit superior performance. Additionally, Fe2O3 helps prevent sedimentation, enhancing the material’s uniformity. A comprehensive performance evaluation using the Entropy Weighted Technique for Order Preference by Similarity to Ideal Solution (EW-TOPSIS) method showed that specimens containing CaO/Fe2O3 exhibited optimal performance, even when considering cost factors.

A review on recent applications of machine learning in mechanical properties of composites

AbstractComposites are undergoing extensive research and utilization due to their excellent mechanical properties, driven by human needs. Traditionally, the research methods in materials science predominantly rely on empirical theory or experimental trial and error approaches. However, the increased complexity of composite materials results in a greater intricacy in their mechanical behavior. Consequently, the utilization of traditional research methods may not achieve sufficient efficiency. Materials science is rapidly transitioning into a data‐driven era, with machine learning (ML) emerging as a potent tool to expedite materials development and enhance properties prediction. Significant advancements have been achieved in the application of ML to the study of composite mechanics. In this review article, we elucidate various ML methods employed in the construction of constitutive models for isotropic and anisotropic composites, and delve into the research on construction ML models that leverage input data derived from composite processes, structures, and environmental conditions to predict material mechanical properties. Additionally, we summarize recent noteworthy ML applications in composite design and optimization. Finally, possible prospective viewpoints are proposed for future development, with the aim of providing essential scientific guidance for advancing material science and technology through ML.Highlights Machine learning can address complexity in constitutive model of the anisotropic composites. Machine learning predicts mechanical properties of composites well by process and structure. Machine learning enhances efficiency in inverse design to optimize composites. Limitations, challenges, development trends of ML in composites.

A novel systematically optimized tabular neural network (TabNet) algorithm for predicting the tensile modulus of additively manufactured PLA parts

Assessing the elastic modulus of 3D-printed polylactic acid (PLA) components is essential for understanding their stiffness and load capacity, which are crucial for predicting product performance and durability. In this study, the predictive accuracy of a Tabular Neural Network (TabNet) algorithm for determining the elastic modulus of 3D-printed PLA components via fused deposition modeling (FDM) was investigated. Utilizing a comprehensive dataset of 128 literature-sourced data points, divided into 80 % for training and 20 % for validation, the study proposed a new Taguchi-based method for efficient hyperparameter optimization of the TabNet algorithm. This optimization revealed that a configuration of 8 decision blocks, 16 attention blocks, and 5 decision steps, along with the "Adam" optimizer, a gamma of 1, learning rate of 0.1, and lambda-sparse of 0.01, yielded the highest prediction accuracy for the elastic modulus of PLA parts. The performance of the optimized TabNet model was evaluated using R-squared (R²), Mean Absolute Error (MAE), Mean Squared Error (MSE), and Root Mean Squared Error (RMSE) measures. The findings highlighted an R² of 96.855 %, an MAE of 0.158, an MSE of 0.037, and an RMSE of 0.193 in the validation dataset, demonstrating substantial predictive reliability. To further test the model’s robustness, fourteen unseen data points were analyzed. The observed discrepancies between predicted and actual values were under 10 %, affirming the Taguchi-optimized TabNet algorithm’s effectiveness in forecasting the elastic modulus of FDM 3D-printed PLA components. This investigation provides a significant advancement in additive manufacturing, introducing a precise and reliable method for predicting the mechanical properties of 3D-printed materials.

Utilizing machine learning to forecast mechanical characteristics of NaOH-Treated jute fiber reinforced composite materials

The prediction of mechanical properties in composite materials is crucial for optimizing their performance in various engineering applications. This study focuses on NaOH treated jute fiber reinforced glass epoxy composites, aiming to predict key mechanical characteristics like flexural strength, tensile strength, and the hardness. A comprehensive dataset of 974 samples was analyzed, encompassing a range of input parameters including fiber content, fiber orientation, matrix type, and processing conditions. Advanced statistical and machine learning techniques were employed to develop predictive models, with XGBoost showing itself to be the best model in terms of predicting each of the three mechanical properties. Feature importance analysis revealed that fiber content is the most significant factor influencing the predictions.

A machine learning–based framework for mapping hydrogen at the atomic scale

Hydrogen, the lightest and most abundant element in the universe, plays essential roles in a variety of clean energy technologies and industrial processes. For over a century, it has been known that hydrogen can significantly degrade the mechanical properties of materials, leading to issues like hydrogen embrittlement. A major challenge that has significantly limited scientific advances in this field is that light atoms like hydrogen are difficult to image, even with state-of-the-art microscopic techniques. To address this challenge, here, we introduce Atom-H, a versatile and generalizable machine learning-based framework for imaging hydrogen atoms at the atomic scale. Using a high-resolution electron microscope image as input, Atom-H accurately captures the distribution of hydrogen atoms and local stresses at lattice defects, including dislocations, grain boundaries, cracks, and phase boundaries. This provides atomic-scale insights into hydrogen-governed mechanical behaviors in metallic materials, including pure metals like Ni, Fe, Ti and alloys like FeCr. The proposed framework has an immediate impact on current research into hydrogen embrittlement and is expected to have far-reaching implications for mapping "invisible" atoms in other scientific disciplines.

Physical and Mechanical Properties of Local Carbon Materials and Warm Compaction Method on the Production of Current Collectors for Light Rail Transit (LRT) Applications

The purpose of this study is to investigate the physical and mechanical properties of local carbon materials and the warm compaction method in the production of current collectors for light rail transit (LRT) applications. The problem here is that the current collectors used by the railway industry in Malaysia for the LRT are still imported from foreign countries which is very costly. Furthermore, the production method of commercial current collectors, namely C-Cu composites, is compact and sintered, which also results in relatively high costs. Therefore, this study focuses on replacing the old materials and methods of commercial current collector production with new materials and methods. This study used a local carbon, which is the kernel shell of oil palm as the main carbon for the production of current collectors. The compact and sintered production methods are then replaced by warm compaction and post-heating methods. The current collectors that had been produced are then cut into several samples to allow them to be tested in anumber of physical and mechanical tests. Based on the test results, when using these new materials and methods, the density and hardness were observed to be slightly lower at 1.81 g/cm3 and 122.6 HRR compared to the commercial current collectors, which have a density of 2.2 g/cm3 and 126.9 HRR. Meanwhile, in the transverse rupture strength (TRS) and resistivity tests, the warm compaction method based on oil palm kernel shell demonstrated higher values of 175.1 MPa and 1631 Ω-cm, respectively, compared to the commercial current collectors which showed values of 58.71 MPa and 598.77 Ω-cm. In conclusion, there are various advantages and disadvantages between the new current collectors and the commercial current collectors in terms of mechanical as well as physical characteristics. Therefore, various improvements and suggestions need to be made in order to produce physically and mechanically better current collectors to be used in LRT applications.

Research on the microstructure and mechanical properties of functional gradient materials of TC4/TC11 titanium alloys for wire arc additive manufacturing with different transitional forms

Functional gradient materials (FGMs) have garnered increasing interest for their potential in material and structural design. Additive manufacturing, as a kind of free manufacturing and near-net shaping technology with in-situ controllability of materials, is the dominant technology for fabricating FGMs. While numerous studies have been conducted on titanium alloy FGMs, there is still a lack of research on the structure and properties of the material with the number of transitional layers. This study employs double-wire arc additive manufacturing to fabricate FGMs composed of TC4 and TC11 alloys. The study examines the utilization of direct and continuous transition forms in conjunction with stress relieving and solution aging heat treatment processes. The composition, grain morphology, microstructure, and mechanical properties of FGMs are analyzed. Results indicate that in samples employing direct transition, higher heat treatment temperatures and durations lead to a more uniform composition and microstructure. Additionally, the interface morphology becomes increasingly indistinct, and transversal elongation at the interface is enhanced by the strain compensation of the two materials. In continuous transitional samples, an increase in the number of transitional layers results in a more uniform microstructure near the interface, leading to a reduction in interface morphology and an enhancement of mechanical properties. The fracture position tends to shift closer to the TC4 side, with both process forms exhibiting ductile fractures. The plasticity of the TC4 part is superior, and the ductile fracture morphology is more pronounced. This study offers a valuable experimental foundation for investigating the direct and continuous transition of titanium alloy FGMs.

Influence of dimensional deviation and thickness non-uniformity on the small-size specimen tensile results of CLF-1 steel

Tensile testing of small-size specimens has been widely used to evaluate the influence of neutron irradiation on the mechanical properties for structural materials of fusion reactors. In recent years, researchers have been trying to standardize small-size specimen tensile test method. In the present paper, we have investigated the influence of dimensional deviation and thickness non-uniformity on the tensile results of small-size specimen by both experiments and finite element simulations, based on one of the candidate structural materials of fusion reactor, i.e. CLF-1 steel. It was found that under the conditions of small grain size, small metallurgical defect size and suitable specimen preparation, the tensile results of SS-J3 specimen could be close to the results of large-size specimen. Slightly higher yield and ultimate strengths for small specimens may be caused by the surface treatment of the wheel grinding. The repeatability of ultimate strength was better than that of yield strength, and the repeatability of elongation was worse than that of strength. For tensile tests on eight SS-J3 specimens, the maximum difference in total elongation was about 3 %. With ±0.1 mm deviation of thickness and parallel width, the maximum variation in total elongation was about 1.8 %. The ductility properties were sensitive to specimen's thickness non-uniformity, the measured uniform and total elongations would obviously decrease even with 0.01 mm thickness non-uniformity.

Molecular dynamics simulation of nanocellulose and cement matrix composites

The interfacial properties of nanocellulose and cement matrix are the key factors affecting the mechanical properties of composite materials. However, it is challenging to study the interface combination through conventional experiments and microscopic characterization techniques. Molecular dynamics simulation (MD), as a nanoscale analytical method, can be used to calculate and analyze the strength, deformation, destruction and interfacial interaction of materials on the atomic scale. Since the existing methods of C-S-H modeling and fiber pull-out from the matrix in molecular dynamics simulations were not suitable for cellulose/C-S-H composite models. In this paper, a molecular dynamics simulation method for nanocellulose cement matrix composites was proposed. Based on the embedded composite model, the tensile stress-strain, interfacial interaction energy, hydrogen bond, and interface failure mode were studied when cellulose was pulled out of the matrix. The results showed that adding cellulose could improve the local ductility and tensile strength of cement matrix materials. The interfacial interaction energy between cellulose and C-S-H was approximately −1.09 J/m2, which was much higher than that between carbon nanotubes and C-S-H. Cellulose would adsorb hydrogen and oxygen atoms on H2O, OH− and silica tetrahedron in C-S-H. In the pull-out simulation of cellulose in C-S-H, C-S-H on the surface of cellulose would be destroyed and attached to the cellulose surface and moved along with it, indicating that cellulose could play a good bridging role in the matrix. The simulation results revealed the action mechanism of cellulose in cement matrix materials.

PVA fiber reinforced red mud-based geopolymer for 3D printing: Printability, mechanical properties and microanalysis

Red mud-based geopolymers are an efficient alternative to resolve the high cement consumption in 3D printed concrete (3DPC). From a materials perspective, good printability and mechanical properties are critical to adopting red mud-based geopolymers in 3DPC. In this study, we selected bauxite tailings-red mud and blast furnace slag to prepare geopolymers. Polyvinyl alcohol (PVA) fibers with 0, 0.3 %, 0.6 %, 0.9 %, and 1.2 % volume fractions were used to reinforce 3D printed red mud-based geopolymers. To evaluate the influence of PVA fiber on the printability and mechanical properties of 3D printed red mud-based geopolymer. We tested the workability, extrudability, structural build-up ability, shape stability, and mechanical properties of the red mud-based geopolymer containing different volume fraction PVA fibers, and a microstructural analysis was performed to reveal the interface bond between the fibers and the geopolymer matrix. The results showed that adding PVA fibers impaired the workability of the red mud-based geopolymer mortar. The red mud-based geopolymer mortar showed a more than threefold increase in extrusion pressure compared to the control mixture (P0) when adding 1.2 % vol fiber. For all other mixtures, the increase was less than twice that of the control mixture. The PVA fiber had a significant positive impact on the structural build-up ability and shape stability of the 3D printable red mud-based geopolymer. In addition, PVA fibers promoted the bending strength of the hardened geopolymer specimens better than the compression strength, and the geopolymer gel on the fibers indicated the good interfacial bonding ability of the PVA fiber. This study demonstrates the feasibility of 3D printed red mud-based geopolymer and the reinforcement of 3D printed red mud-based geopolymer by PVA fibers, providing a material perspective to increase the range of red mud applications in 3D printed concrete.

Multi-scale analysis of ultimate bearing capacity in composite hull joints: failure mechanism and numerical simulation

ABSTRACT Progressive failure analysis method is the main method to analyse the ultimate bearing capacity and failure mode of composite structures. Multi-scale method can effectively reduce the dependence of damage mode and stiffness degradation analysis on material parameters. Based on the multi-scale method, from micro-scale to mesoscale and then to macro-scale, the equivalent modulus and equivalent strength of fibre bundles, single-layer laminates and multi-directional laminates were predicted respectively, and the prediction method of ultimate bearing capacity of large-scale composite structures from material level to structure level was constructed. The mechanical properties of standard composite materials and the ultimate bearing capacity of full-scale composite joints were tested respectively, and the ultimate bearing capacity and failure mode of L-joints were predicted by numerical method. The results show that the numerical simulation method based on multi-scale can accurately predict the ultimate bearing capacity and failure mode of large-scale joints of the hull.

Interaction between calcium hydroxide and calcium-alumino-silicate-hydrate on micromechanical properties

Calcium-alumino-silicate-hydrate (C-A-S-H) and calcium hydroxide (CH) are the two primary hydration products that play crucial roles in the mechanical properties of cementitious materials, particularly in the viscoelastic behavior known as creep. This study used hydrated C3S and a mixture of the synthesized C-A-S-H and CH to identify the interactions between CH and C-A-S-H. The interactions that dominate the mechanical properties mainly operate from physical and chemical perspectives. CH exhibited a filling effect on C-A-S-H in the physical interactions, demonstrating multi-scale particle packing efficiency. The particle size of CH per unit volume of the mixture was proposed as a critical parameter for the filling effect. Regarding chemical interactions, the synthetic system exhibits interactions primarily through van der Waals forces through compaction. In contrast, the interaction in the hydration system primarily originates from the strong atomic bonding between C-A–S–H and CH at the nanoscale.

Investigation of phase transformation model, densification mechanism, and mechanical properties of TiH2 powder metallurgy materials

TiH2 has gradually gained attention in powder metallurgy because of its unique properties. This study systematically investigated the porosity, density, mechanical tensile properties, and fracture toughness of sintered samples of TiH2 as a powder metallurgy starting material. The results showed that, compared with hydrogenation-dehydrogenation titanium (HDH Ti), the density, elongation, and fracture toughness of the sintered TiH2 samples significantly improved. In addition, the contributions of grain size, porosity, and oxygen content to the yield strength of the samples are discussed, and the results revealed that a lower oxygen content and porosity are the main reasons for the differences in the mechanical properties between HDH Ti and TiH2. Finally, the experimental results are combined with first-principles calculations and simulations to construct a TiH2 phase transition model. The contribution of H atoms to the TiH2 phase transition energy barrier and activation sintering densification was investigated and elucidated, revealing the TiH2 sintering densification mechanism from the perspective of phase transition. The derived results contribute to a deeper understanding of the intrinsic mechanism of TiH2 activation sintering densification, which is highly important for the development of advanced titanium materials.

Hydrogen modified dislocation loop types and shapes in irradiated iron

Dislocation loops are one type of irradiation defects that severely degrade the mechanical properties of nuclear materials. In this study, we found that hydrogen atoms in irradiation environment significantly modify the loop properties including loop types and shapes during in-situ hydrogen irradiation. <100> loops have been energetically stable from 300 °C in H+ irradiated iron whereas the stability of <100> loops is delayed until 500 °C in Fe+ irradiated iron. Meanwhile, both <100> loops and 1/2<111> loops exhibit polygonal shapes with sharp corners at 400 °C after H+ irradiation, similar to loops predicted at 900 °C without hydrogen. Our results highlight the importance of considering the hydrogen effects in dislocation loop evolution and stability.

Evaluation of Mechanical Properties of Composite Material with a Thermoplastic Matrix Reinforced with Cellulose Acetate Microfibers

Low-density polyethylene (LDPE) has been widely used in various applications due to its flexibility, lightness, and low production cost. However, its massive use in disposable products has raised environmental concerns, prompting the search for more sustainable alternatives. This study aims to investigate the mechanical properties achievable in a composite material utilizing low-density polyethylene (LDPE), potato starch (PS), and cellulose microfibrils (MFCA) at loadings of 0.05%, 0.15%, and 0.30%. Initially, the cellulose acetate microfibrils (MFCA) were produced via an electrospinning process. Subsequently, a dispersive mixture of the aforementioned materials was created through the extrusion and pelletizing process to form pellets. These pellets were then molded by injection molding to produce test specimens in accordance with ASTM D 638, the standard for tensile strength testing. The evaluation of the properties was conducted through mechanical tensile tests (ASTM D638), hardness tests (ASTM D 2240), melt flow index (ASTM D1238), and scanning electron microscopy (SEM). This study determined the influence of cellulose acetate microfibril loadings below 0.3% as reinforcement within a thermoplastic LDPE matrix. It was demonstrated that these microfibrils, due to their length-to-diameter ratio, contribute to an enhancement in the mechanical properties.