Mechanical Characteristics Of Material Research Articles

Impact of different parameters in tribological properties of enset ventricosum/ terminalia arjuna fibers /SiO2 filler incorporation

Natural fiber composites have garnered considerable interest in recent years as sustainable substitutes for synthetic materials, owing to their environmental advantages, including renewability, biodegradability, and cost-effectiveness. Notwithstanding these benefits, there is a vital need to improve the mechanical and tribological characteristics of these composites for applications involving significant wear. This work used compression molding to make hybrid composites with natural fibers (NFs) and nano silicon dioxide (nSiO2) filler. The matrix material was epoxy, and the natural reinforcements were Enset ventricosum (EV) and Terminalia arjuna (TA) fibers. Tensile (TS), flexural (FS), and impact (IS) characteristics improved using 1:1 SiO2 filler and EV/TA fiber reinforcement. The combination of 6 wt% SiO2 and 45 wt% EV/TA improved mechanical performance. A high SiO2 filler (6 wt%) in polymer-based composites decreased Specific Wear Rate (SWR), according to Taguchi optimization. A better fiber-matrix interaction improves the mechanical characteristics of materials with fillers. This study optimized several responses using the new combined compromise solution (CoCoSo) method. Multi-criteria decision making is used here. This study introduces Method based on the Removal Effects of Criteria (MEREC) to determine objective criteria weights. Conclusions from experiments show ideal results. CoCoSo's optimization study showed that Enset ventricosum and Terminalia arjuna fiber (EV/TA) hybridization affected composites' tribological behavior.This hybrid fiber combination carried the most influence, followed by fillers. The optimal results were obtained with 6 wt% SiO2/25 wt% EV/TA Hybrid fiber, 1000 m Sliding distance (SD), 2 m/s Sliding speed (SS), and 10 N axial load (AL).

Investigation of mechanical properties on functionally graded material reinforced with graphene nanoplatelets for biomedical applications

ABSTRACT This research focuses on the mechanical characterization of FG material graded with Graphene nano-platelets (GPLs) in the transverse direction. Different weight percentages of GPL (0–2 wt. %) were incorporated into epoxy resin for manufacturing the FGM using a simple casting method and the effects were analyzed. This paper aims to enhance the material’s performance, especially focusing on its potential use in biomedical tools. Mechanical tests including assessment on tensile, flexural, impact strength, and microhardness demonstrated substantial improvement in strength and stiffness as compared to other nanocomposite structures. Microstructural analysis using scanning electron microscopy (SEM), Fourier-Transform Infrared Spectroscopy (FTIR), and X-ray Diffraction (XRD) analysis which hint at the strong chemical interaction and physical association of GPL nanofiller with the epoxy resin. Thermal analysis was conducted using the Dynamic Mechanical Analysis (DMA) test, which revealed enhanced thermal stability of the FG specimen with a higher glass transition temperature than other carbon nanofillers mixed in epoxy resin. This is advantageous for the FG material to maintain its glassy state, maintaining safety and reliability during high-temperature medical applications. All these findings indicate that the proposed FG-GPL material possesses the necessary mechanical properties, suggesting that customized nanofiller integration could lead to significant advancements in medical procedures, such as in vivo stomach biopsy treatments, drug delivery systems, etc. The material also meets specific anatomical requirements and reduces the risk of malfunction, thereby ensuring patient safety as justified by current experimental investigations.

Fine Structural Analysis of Degummed Fibroin Fibers Reveals Its Superior Mechanical Capabilities.

Bombyx mori silk fibroin fibers constitute a class of protein building blocks capable of functionalization and reprocessing into various material formats. The properties of these fibers are typically affected by the intense thermal treatments needed to remove the sericin gum coating layer. Additionally, their mechanical characteristics are often misinterpreted by assuming the asymmetrical cross-sectional area (CSA) as a perfect circle. The thermal treatments impact not only the mechanics of the degummed fibroin fibers, but also the structural configuration of the resolubilized protein, thereby limiting the performance of the resulting silk-based materials. To mitigate these limitations, we explored varying alkali conditions at low temperatures for surface treatment, effectively removing the sericin gum layer while preserving the molecular structure of the fibroin protein, thus, maintaining the hierarchical integrity of the exposed fibroin microfiber core. The precise determination of the initial CSA of the asymmetrical silk fibers led to a comprehensive analysis of their mechanical properties. Our findings indicate that the alkali surface treatment raised the Young's modulus and tensile strength, by increasing the extent of the fibers' crystallinity, by approximately 40 % and 50 %, respectively, without compromising their strain. Furthermore, we have shown that this treatment facilitated further production of high-purity soluble silk protein with rheological and self-assembly characteristics comparable to those of native silk feedstock, initially stored in the animal's silk gland. The developed approaches benefits both the development of silk-based materials with tailored properties and the proper mechanical characterization of asymmetrical fibrous biological materials made of natural building blocks.

Effect of Yb3+ on the thermophysical and mechanical properties of gadolinium zirconate ceramics: First-principles calculations and experimental study

Thermal barrier coating materials require high phase stability, low thermal conductivity, and a thermal expansion coefficient that matches the bonding layer. Cation doping is a highly efficient method for enhancing the thermophysical and mechanical characteristics of materials used in thermal barrier coatings. The thermophysical and mechanical properties, as well as the phase stability at high temperatures of ceramic materials doped with Yb3+ in gadolinium zirconate, are examined by utilizing first principles calculations and solid-state reaction methods. As the Yb3+ content increases, the grain average particle size of gadolinium zirconate ceramics first decreases and then increases. Given that a smaller grain size results in more grain boundaries, thereby reducing the thermal conductivity of the material, it can be inferred that Yb0.20 ((Gd0.8Yb0.2)2Zr2O7) with the smallest grain size exhibits lower thermal conductivity. As the Yb3+ content increases, both the calculated and experiment results suggest the Young’s modulus of gadolinium zirconate initially declines to its minimum value when the Yb3+ content is 0.5 and subsequently experiences a little increase. Furthermore, as the concentration of Yb3+ increases, the material initially experiences a drop in both hardness and fracture toughness, followed by a subsequent increase. Both the calculation and experimental results indicate that the thermal conductivity of gadolinium zirconate initially decreases and then increases. Among the different compositions, Gd1.5Yb0.5Zr2O7 demonstrates the minimum thermal conductivity, measuring 1.029 W/(m⸱K) according to the Clark model and 1.152 W/(m⸱K) according to the Cahill model. At a temperature of 1273 K, the experimental results demonstrated that (Gd0.8Yb0.2)2Zr2O7 has the lowest thermal conductivity of 1.415 W/(m·K). Furthermore, both the calculated and experimental thermal expansion coefficients of the material decrease first until the Yb3+ concentration is 0.5 and then increase slightly when the Yb3+ content increases. Moreover, gadolinium zirconate ceramics have demonstrated a consistent single-phase fluorite structure, excellent stability at high temperatures, and remarkable structural integrity during repeated heating and cooling cycles. The calculation results exhibit strong congruence with the experimental data. The objective of this work is to improve the thermophysical and mechanical properties of gadolinium zirconate ceramics for their application as materials for thermal barrier coatings.

Towards Simpler Modelling Expressions for the Mechanical Characterization of Soft Materials

Aims: The aim of this paper is to develop a new, simple equation for deep spherical indentations. Background: The Hertzian theory is the most widely applied mathematical tool when testing soft materials because it provides an elementary equation that can be used to fit force-indentation data and determine the mechanical properties of the sample (i.e., its Young’s modulus). However, the Hertz equation is only valid for parabolic or spherical indenters at low indentation depths. For large indentation depths, Sneddon’s extension of the Hertzian theory offers accurate force-indentation equations, while alternative approaches have also been developed. Despite ongoing mathematical efforts to derive new accurate equations for deep spherical indentations, the Hertz equation is still commonly used in most cases due to its simplicity in data processing. Objective: The main objective of this paper is to simplify the data processing for deep spherical indentations, primarily by providing an accurate equation that can be easily fitted to force-indentation data, similar to the Hertzian equation Methods: A simple power-law equation is derived by considering the equal work done by the indenter using the actual equation. Results: The mentioned power-law equation was tested on simulated force-indentation data created using both spherical and sphero-conical indenters. Furthermore, it was applied to experimental force-indentation data obtained from agarose gels, demonstrating remarkable accuracy. Conclusion: A new elementary power-law equation for accurately determining Young’s modulus in deep spherical indentation has been derived.

Mechanical heterogeneity characterization of coal materials based on nano-indentation experiments

Mechanical heterogeneity characterization of coal materials based on nano-indentation experiments

Experimental analysis of the cyclic behavior of rammed earth walls reinforced with arundo donax natural fiber

This experimental study analyzes the seismic behavior of rammed earth walls with Arundo donax natural fiber inclusions, also called "caña brava” (REWC), and without inclusions (REW). The experimental program consists of two stages: physical and mechanical characterization of materials, where properties such as particle size, density, Atterberg limits, and compressive and flexural strength were determined; and dynamic tests, which included compressive and cyclic load tests on REW and REWC walls. The walls were subjected to cyclic loading with derivatives between 0.2 % and 1.4 % in-plane combined with a constant vertical compressive stress of 13 kPa to simulate seismic forces in the presence of gravity loads. The results regarding loading, hysteretic response, energy dissipation, stiffness degradation, and failure mode are compared. In addition, the envelope curves of the load-displacement hysteretic responses are analyzed using a capacity spectrum approach. It is observed that the inclusion of Arundo donax natural fiber negatively affects the mechanical properties of the walls and their hysteretic response. It is also observed that the energy dissipation is affected by the inclusion of Arundo donax natural fiber. However, the stiffness behavior is similar in all the walls. Rigid body failure modes are identified in all the walls, but the walls, including Arundo donax natural fiber, form failure planes that divide the wall into two bodies.

Preparation and mechanical characterization of natural polymer composite material obtained from fox tail palm seeds

This experimental investigation reveals the preparation of natural composite material from foxtail palm tree seeds. The fruits from the foxtail palm tree are used for the extraction of oil, and the by-product of the extraction process is freely dumped. This study attempts to utilize the waste by-product of foxtail palm tree fruit as a valuable natural composite material. The fabrication was done using the hand lay-up method for the proposed reinforcement (4% and 8%) of filler materials. The obtained composite materials are subjected to significant mechanical characterization of tensile behaviour, flexural property, and hardness. In addition, the morphological study was also carried out by the scanning electron microscope (SEM). The results show that, as the reinforcement percentages of filler material increase, the mechanical properties are improved. This may be due to the uniform dispersion of natural fibres in the polymer. The tensile strength was improved by 22.43% and 29.08% for 4% and 8% filler reinforcement. Similarly, the stiffness property was improved by 9.32% for 4% reinforcement and 18.68% for 8% reinforcement when compared with neat composite. The SEM images reveal the failure analysis, bonding strength and fibre pull-out in the composites. Finally, the foxtail fruit fibre shows promise as a reinforcing agent in composite materials, improving their mechanical properties and making them suitable for various applications requiring strength, stiffness, and resistance to deformation.

MODERN APPROACHES TO THE USE OF COMPOSITE MATERIALS IN CONSTRUCTION

A review of the literature on scientific approaches in the development of composite materials and building structures made of composites is carried out. When creating and manufacturing traditional and new composite materials, for example, by additive manufacturing, and when creating structures and structures in engineering calculations, new techniques, finite element computational software systems, and neural network technologies are used, which are used in the creation of modern metal and composite materials, analysis of mechanical characteristics of materials, forecasting loads on the structure, optimization of structures and calculation of their construction characteristics. The distinctive features of modern composite materials are shown. The main types of composite materials are considered: talc, diatomite, calcium carbonate, gibbsite, barium sulfate, feldspar, nepheline, aragonite, calcium carbonate, wool, silk, cotton, linen, jute, wood pulp, asbestos, fiberglass, metal fibers, quartz fibers, basalt fibers, polyamide fibers, polyester fibers, polyvinyl alcohol fibers, carbon fibers, viscose fibers. The physical and mechanical characteristics of composite materials (based on epoxy, aluminum, carbon, magnesium, and nickel matrices) and traditional (steel, aluminum, brick, concrete) building materials are presented. The disadvantages of such composite materials as carbon fiber, fiberglass, organoplastics, textolite, carbon concrete, and polystyrene concrete are presented. Deformation diagrams of some types of fibers for composite materials are considered: high-modulus carbon fibers, high-strength carbon fibers, aramid fibers, glass fibers, and basalt fibers. The advantages of the system of external reinforcement of building structures with composite materials are described. Examples of reinforcement of building structures are considered: reinforced concrete reinforcement; reinforcement of floor slabs; reinforcement of columns; and reinforcement of brick walls.

Effect of the electric field on the free volume investigated from positron annihilation lifetime and dielectric properties of sulfonated PVC/PMMA

AbstractPolymer electrolyte membranes (PEMs) play a vital role in electrochemical devices, facilitating ion conduction while blocking gases and electrons. Their effectiveness is closely linked to their microstructural properties, especially the free volume, which impacts ionic conductivity, mechanical strength, and overall device performance. This study examines the behavior of PVC/PMMA/SSA blends under electric fields, using Positron Annihilation Lifetime Spectroscopy (PALS) to assess free volume and dielectric properties. The study involved preparing and characterizing membranes through x‐ray diffraction (XRD), thermogravimetric analysis (TGA), and PALS. XRD results indicated semi‐crystalline structures with changes in intensity due to temperature variations, while TGA highlighted changes in thermal stability under different electric fields. PALS measurements showed that free volume varied with temperature and electric field strength, influencing the material's dielectric and mechanical characteristics. The results revealed that higher electric fields reduced free volume while enhancing dielectric properties. The dielectric constant and loss were found to depend on frequency, which was affected by the polar SO3H groups. Impedance spectroscopy provided further insights into the electrical properties, showing increased dc conductivity with stronger electric fields. A correlation between the free volume investigated from PAL and the electrical properties was observed. This study emphasizes the significance of free volume and external electric field in optimizing PEMs for advanced energy applications.

Mechanical Properties and Material Characterization of Magneto-Thermal Sensitive Hydrogels

When in an alternating magnetic field, magneto-thermal sensitive hydrogels can absorb solvent molecules, causing the gel network to swell several times to its original size. By conducting experiments with magnetic PNIPAm hydrogels (M-PNIPAm), the parameters of the theoretical model for magneto-thermal sensitive hydrogels were experimentally determined. Subsequently, the mechanical behavior of M-PNIPAm hydrogel was studied through finite element analysis and tensile experiments. The numerical calculations based on the thermodynamic model with specific parameters showed consistency with experimental results. The comparison indicated that the proposed theory for magneto-thermal sensitive hydrogels can accurately predict the mechanical property of M-PNIPAm hydrogel, providing theoretical support for investigating large deformation of magneto-thermal sensitive hydrogels. Furthermore, we discovered that the variation of magnetic particle content significantly influence the mechanics properties of hydrogel. Our findings provide valuable insights for the research and application of magneto-thermal sensitive hydrogels.

Compression creep behaviors of GH4169 cylinder entangled wire material at elevated temperatures

As a nickel-based alloy, GH4169 has the properties of excellent corrosion resistance, high temperature oxidation resistance and high creep resistance. In this paper, the compression creep behaviors of cylinder entangled wire materials (CEWMs) made from metal wires (GH4169 nickel-based alloy, 304 stainless steel) were investigated at elevated temperatures (from 400 °C to 500 °C). The performance degradation of the two materials was evaluated by the variation amplitude of four mechanical properties parameters and material characterization methods. The results indicated that both of 304 CEWMs and GH4169 CEWMs suffered a significant performance degradation at elevated temperatures, and both of the two CEWMs showed a much serious performance degradation above 450 °C (tempering temperature). Compared to the 304 CEWMs at the tested temperatures, the GH4169 CEWMs obtained better creep resistance. It is therefore concluded that the GH4169 CEWM is an excellent material that can replace the commonly used 304 CEWM at elevated temperature work conditions.

Quantifying uncertainty in fatigue crack growth of SLM 316L through advanced predictive modeling

AbstractOptimizing structural designs is crucial today, with additive manufacturing, particularly selective laser melting, gaining prominence. Thorough mechanical characterization of new materials remains vital. This paper investigates fatigue crack growth behavior in SLM 316L specimens under cyclic loading conditions. The study addresses result uncertainties by using CT specimens aligned along three building directions per ASTM E647 standards and a constant loading ratio (R = 0.1), necessitating mean value and confidence interval predictions. Departing from linear prediction models, innovative Bootstrap Polynomial and Power Regression Models and Bayesian Nonlinear Regression Model updated posterior distribution by Markov Chain Monte Carlo are employed. These approaches leverage bootstrapping to construct confidence intervals, offering robustness and flexibility in handling non‐normal data behavior and limited sample sizes. They provide tailored fits to data curvature, revealing limitations of linear prediction models in capturing observed nonlinear behavior, enhancing reliability in additive manufacturing applications, and advancing material science and engineering.

Baya Project: Building Structural Shells in Wicker

The growing of natural fibres ‐ such as wicker ‐ is deeply virtuous: it helps to diversify the forest cover, itrequires limited inputs ??? even in water, little maintenance, and its CO2 emissions are minimal. Their uses in basketry date back to the Neolithic period, and even probably before. People around the world have employed braiding technics and basketry craft to design a large panel of objects, clothes, furniture, boats, etc. In the field of architecture and construction, we can identify natural fibre uses in numerous of vernacular shelters, but they are generally limited to non-structural filling elements. The scarcity of mechanical characterization of wicker material in the literature is underlying that, since now, these kinds of materials are not commonly used to a structural purpose. The aim of our research is to demonstrate the feasibility to design and build structural wicker braided shells for architectural purposes, and to provide designers with the necessary tools for this process. Thanks to wicker mechanical characterization and to experimental measurements, we developed a law which defines a relation between density and orientation of the stems and the fields of principal stresses on an idealized continuous surface: “each field of stress is related to an optimal braiding”. These data have supplied an algorithm, BAYA, making design and optimization of braided shells accessible and easy to use for architects and practitioners. Even if our research focused on wicker, it should be easily adaptable to other fibres and plants as, for instance ,rattan or reed. This innovative research is demonstrated by the realization of a full-scale public pavilion hanging from trees on the belvedere of the Butte du Chapeau Rouge park (Paris XIX), and a 12.8‐meter-long footbridge for the Utopies Constructives festival in Richelieu’s Park.

Mechanical characterization and constitutive modeling of additively-manufactured polymeric materials and lattice structures

Additively manufactured polymeric lattice structures are being extensively studied, primarily because their mechanical properties can be tailored by controlling the unit cell geometry, giving them higher designability than stochastic materials. However, the inherent layer-wise additive manufacturing process affects the base material properties related to the printing direction, which in turn affects the macroscopic responses of the entire lattice materials. A robust understanding and modeling of lattice structures' elastic and plastic yield behavior in a homogenized approach are essential to enhance their design and analysis efficiency in engineering applications. In pursuit of this goal, a unified printing angle-dependent constitutive model of base materials is proposed in line with the tensile experimental data. The elastic material properties (elastic modulus, shear modulus, and Poisson's ratio), obtained through numerical simulations of one unit-cell with periodic boundary conditions, exhibit anisotropic properties, with the degree of anisotropy determined by the angle of the constituent members and base materials. Furthermore, both experimental and numerical results of lattices demonstrate anisotropic mechanical response under horizontal and vertical compression. Virtual multiaxial experiments are conducted through multi-cell numerical simulations, enabling the determination of initial yielding points of two different lattice structures (Kelvin and Simple cubic and body-centered cubic hybrid structures) under various loading conditions using a dissipation energy-based criterion. Overall, the multiaxial yield surface of the investigated lattices under various stress states, except for the isotropic principal stress plane, can be properly depicted by the Extended-Hill anisotropic yield criterion.

A general hyperelastic model for rubber-like materials incorporating strain-rate and temperature

A comprehensive hyperelastic model that precisely forecasts the mechanical characteristics of materials with rubber-like qualities is presented. This model relies on the well-established five-parameter Mooney-Rivlin model, which is then extended to incorporate strain rate dependent and temperature dependent term. To validate its accuracy, experimental data from ethylene propylene diene monomer (EPDM) rubber materials was utilized to compare with the model prediction. Hyperelastic stress-strain curves were collected from a variety of materials that were subjected to varying temperatures and strain rates to improve the model’s applicability. Its prediction results are compared against the collected experimental data, resulting in consistent and reliable outcomes. The simplified form of the model not only establishes an effective framework for characterizing and predicting the mechanical response of materials that resemble rubber under different working conditions but makes the coding and implementation of finite element analysis easier.

Micro and macro mechanical characterization of artificial cemented granular materials

Micro and macro mechanical characterization of artificial cemented granular materials

The effect of span length on the flexural properties of glass and basalt fiber reinforced sandwich structures with balsa wood core for sustainable shipbuilding

The current research aims to analyze the mechanical characterization of sandwich materials through a three-point flexural test. The sandwich structures in question composed of balsa wood as a core and four different types of fiber reinforced vinyl ester composite facesheets, namely Glass, Basalt, Glass/Carbon, and Basalt/Carbon. The sandwich panels were prepared using the vacuum infused processing method. The primary objective of this investigation is to explore the feasibility of utilizing basalt fibers for the production of structural parts in shipbuilding and replacing the already existed glass fibers. The flexural test was carried out with using three-point flexural test with varying the span length from 120 mm, 180 mm, 220 mm. Additionally, an analysis of variance (ANOVA) was then carried out to compare the mean values of properties deduced from these tests. The results showed that using basalt fibers instead of glass fiber reinforced enhanced the flexural stiffness of the sandwich structure. The flexural strength and modulus are shown to depend on span length and fiber type. The flexural modulus increases with an increase in span length. Similarly, flexural strength increases in glass fiber-based structures, while a slight reduction is observed in basalt fiber-reinforced structures the larger span length. The findings of this research suggest that basalt fibers hold potential as a replacement for glass fibers in producing structural components in shipbuilding. These results offer valuable information that can aid in the design and optimization of sandwich materials in shipbuilding.

Ductile Fracture of Titanium Alloys in the Dynamic Punch Test

Estimates of physical and mechanical characteristics of materials at high strain rates play a key role in enhancing the accuracy of prediction of the stress–strain state of structures operating in extreme conditions. This article presents the results of a combined experimental–numerical study on the mechanical response of a thin-sheet rolled Ti-5Al-2.5Sn alloy to dynamic penetration. A specimen of a titanium alloy plate underwent punching with a hemispherical indenter at loading rates of 10, 5, 1, and 0.5 m/s. The evolution of the rear surface of specimens and crack configuration during deformation were observed by means of high-speed photography. Numerical simulations were performed to evaluate stress distribution in a titanium plate under specified loading conditions. To describe the constitutive behavior and fracture of the Ti-5Al-2.5Sn alloy at moderate strain rates, a physical-based viscoplastic material model and damage nucleation and growth relations were adopted in the computational model. The results of simulations confirm a biaxial stress state in the center of specimens prior to fracture initiation. The crack shapes and plate deflections obtained in the calculations are similar to those observed in experiments during dynamic punching.

Characterization of Anisotropic Salt Weathering through Nondestructive Techniques Mapping Using a GIS Environment.

Doctrinal texts on architectural heritage conservation emphasize the importance of fully understanding the structural and material characteristics and utilizing information systems. Photogrammetry allows for the generation of detailed, geo-referenced Digital Elevation Models of architectural elements at a low cost, while GIS software enables the addition of layers of material characteristic data to these models, creating different property maps that can be combined through map algebra. This paper presents the results of the mechanical characterization of materials and salt-related decay forms of the polygonal apse of the 13th-century monastery of Santa María de Bonaval (Guadalajara, Spain), which is primarily affected by salt crystallization. Rock strength is estimated using on-site nondestructive testing (ultrasound pulse velocity and Leeb hardness). They are mapped and combined through map algebra to derive a single mechanical soundness index (MSI) to determine whether the decay of the walls could be dependent on the orientation. The presented results show that salt decay in the building is anisotropic, with the south-facing side of the apse displaying an overall lower MSI than the others. The relative overheating of the south-facing side of the apse enhances the effect of salt crystallization, thereby promoting phase transitions between epsomite and hexahydrite.