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Highlights Environmental hazards caused by the ever‐increasing end‐of‐life (EoL) glass fiber reinforced polymer (GFRPs) composite waste is of major concern for the sustainable development of the industry. Compared to land filling or incineration, pyrolysis is one of the most promising environmentally friendly methods of disposal of EoL GFRPs. Pyrolysis not only results in recovery of clean glass fibers but other valuable products, such as oils. However, long processing time at elevated temperature leads to aggravation of already existed surface flaws along with the structural changes. Therefore, thermal conditioning of glass fibers results in severe deterioration of the strength in recovered fibers and hence limiting the use of recovered fibers to low end‐products. In this study, a new strategy was adopted where instead of complete cleaning of the fibers at pyrolysis stage, the fibers were partially oxidized and the complete removal of char from the surface of glass was done during hot alkaline etching. This strategy was opted to enhance the quality of the required fibers while reducing the processing time. The results showed ~200% increase in strength of fibers after the combined treatment of pyrolysis and post etching compared to the just pyrolyzed samples with etching time of just 1 min. End‐of‐life panels of GFRPs were pyrolyzed under inert environment of Argon. Residual char was partially removed through post oxidation under flowing air. Hot alkaline etching resulted in complete removal of char and surface defects. Partial oxidation and short etching cycles resulted in improved strength of recovered glass fibers. [ABSTRACT FROM AUTHOR]

Digital Image Correlation (DIC) often encounters challenges with variability and consistency in traditional speckle pattern application techniques, such as spray-painting, affecting measurement accuracy and reliability. This study evaluates a film-free water decal method as an alternative for applying speckle patterns in DIC. SS275 structural steel specimens were prepared with speckle patterns using both the film-free water decal method and traditional spray-painting. The quality of the speckle patterns was assessed, and their effectiveness for DIC was evaluated through tensile testing and a comparison with strain gauge measurements. The film-free water decal method provided enhanced control over speckle pattern application, resulting in high-quality, consistent patterns. Strain measurements obtained using this method closely matched those from traditional methods, confirming its reliability. The film-free water decal method offers a practical and reliable alternative to spray-painting, improving the consistency and accuracy of DIC experiments, with potential applications in various engineering and scientific fields. [ABSTRACT FROM AUTHOR]

Background: There are a limited number of commercially available sensors for monitoring the deformation of materials in-situ during harsh environment applications, such as those found in the nuclear and aerospace industries. Such sensing devices, including weldable strain gauges, extensometers, and linear variable differential transformers, can be destructive to material surfaces being investigated and typically require relatively large surface areas to attach (> 10 mm in length). Digital image correlation (DIC) is a viable, non-contact alternative to in-situ strain deformation. However, it often requires implementing artificial patterns using splattering techniques, which are difficult to reproduce. Objective: Additive manufacturing capabilities offer consistent patterns using programmable fabrication methods. Methods: In this work, a variety of small-scale periodic patterns with different geometries were printed directly on structural nuclear materials (i.e., stainless steel and aluminum tensile specimens) using an aerosol jet printer (AJP). Unlike other additive manufacturing techniques, AJP offers the advantage of materials selection. DIC was used to track and correlate strain to alternative measurement methods during cyclic loading, and tensile tests (up to 1100 µɛ) at room temperature. Results: The results confirmed AJP has better control of pattern parameters for small fields of view and facilitate the ability of DIC algorithms to adequately process patterns with periodicity. More specifically, the printed 100 μm spaced dot and 150 μm spaced line patterns provided accurate measurements with a maximum error of less than 2% and 4% on aluminum samples when compared to an extensometer and commercially available strain gauges. Conclusion: Our results highlight a new pattern fabrication technique that is form factor friendly for digital image correlation in nuclear applications. [ABSTRACT FROM AUTHOR]

Material Extrusion (MEX), particularly Fused Filament Fabrication (FFF), is the most widespread among the additive manufacturing (AM) technologies. To further its development, understanding the influence of the various printing parameters on the manufactured parts is required. The effects of varying the infill percentage, the number of layers of the top and bottom surfaces and the number of layers of the side surfaces on the tensile properties of the printed parts were studied by using a full factorial design. The tensile test results allowed a direct comparison of each of the three parameters' influence on the tensile properties of the parts to be conducted. Yield strength appears to be the most affected by the number of layers of the top and bottom surfaces, which has twice the impact of the number of layers of the side surfaces, which is already twice as impactful as the infill percentage. Young's modulus is the most influenced by the number of layers of the top and bottom surfaces, then by the infill percentage and finally by the number of layers of the side surfaces. Two mathematical models were considered in this work. The first one was a polynomial model, which allowed the yield strength to be calculated as a function of the three parameters mentioned previously. The coefficients of this model were obtained by performing tensile tests on nine groups of printed samples, each with different printing parameters. Each group consisted of three samples. A second simplified model was devised, replacing the numbers of layers on the side and top/bottom surfaces with their fractions of the cross-section surface area of the specimen. This model provided results with a better correlation with the experimental results. Further tests inside and outside the parameter ranges initially chosen for the model were performed. The experimental results aligned well with the predictions and made it possible to assess the accuracy of the model, indicating the latter to be sufficient and reliable. The accuracy of the model was assessed through the R2 value obtained, R2 = 92.47%. This was improved to R2 = 97.32% when discarding material infill as an input parameter. [ABSTRACT FROM AUTHOR]

In this study, the surface of the raw Musa acuminata peduncles fiber (MAPF) was modified by using a 5 (w/v) % alkali solution. MAPF was immersed in an alkali solution for different soaking durations such as 15, 30, 45, 60, and 75 min. After the alkalization, chemical analyses were conducted for raw and alkalized fibers. The outcome of the chemical analysis revealed that 60 min of soaking time is optimal since it has a higher cellulose fraction (74.22 wt.%) than raw (66.43 wt.%) and alkalized fibers with other soaking durations. Reduced diameter (51.46 µm from 64.74 μm) and slightly increased density (992 kg/m3 from 942 kg/m3) of the optimally alkalized MAPF were established through physical analyses. The Fourier transform infrared spectroscopy and nuclear magnetic resonance spectroscopy witnessed the eradication of amorphous fraction from the optimally alkalized MAPF. The suitability of raw and optimally alkalized MAPF as reinforcement in polymer composites used in high-temperature working environments were analyzed through thermogravimetric analysis, which proved that MAPF-reinforced plastics could be used up to 175 °C. Improvements in the bonding ability of the optimally alkalized MAPF with polymer matrix were authorized by scanning electron microscope and atomic force microscope analysis. Enhancement in the single fiber tensile strength (96.5 ± 32.7 to 162 ± 53.7 MPa) and tensile modulus (2.22 ± 0.976 to 3.46 ± 0.846 GPa) of the optimally alkalized MAPF were corroborated by single fiber tensile testing. [ABSTRACT FROM AUTHOR]

The printing process parameters are important in producing coconut polypropylene (CcPP) products by filament composite in the additive manufacturing industry. Fused deposition modeling techniques in 3D printing applications have considered multiple parameters to meet good finishing parts. This study uses comprehensive measurements to identify the best printing parameter for evaluating the composite properties. Complete deposition, unwrapping, good finishing, and adequate heat are the qualitative printing process parameters used to finalize the optimum nozzle and bed temperature of the CcPP filament composite. The range between 50°C to 80°C and 225°C to 245°C for bed and nozzle temperatures were used to achieve a well surface and successful production. After multiple trials of printing the CcPP filament composite, the optimal bed and nozzle temperatures were found to be 80°C and 230°C, respectively. Two types of infill density were used to analyze the effect on the tensile properties of CcPP filament composite. The result showed that 50% infill density was higher for both 1% and 5% fiber loading than 25% infill density for tensile strength with 15.65 and 22.87 MPa compared to 12.93 and 16.59 MPa. The same pattern as the score of Young's moduli of 50% infill density was higher than 25% infill density for 1% and 5% fiber loadings with 479.52 and 641.23 MPa compared to 400.17 and 493 MPa. Qualitative and quantitative measurements of printing process parameters and properties help reduce the time and cost and benefit 3D printer users in the industry. [ABSTRACT FROM AUTHOR]

Nanomaterials, particularly nanofibers produced through electrospinning, have garnered significant attention due to their unique properties and diverse applications. This research explores the influence of collector design, electrode geometry, and collector speed on the properties of electrospun polyacrylonitrile (PAN) nanofibers. Finite element analysis (FEA) was employed to simulate electric fields, revealing the impact of collector geometry on field intensity. The experimental setup, enclosed in an isolated chamber, employed various collector types and electrode configurations. Scanning electron microscope (SEM) analysis showcased the effect of collector speed on fiber alignment and diameter. Furthermore, FEA simulations elucidated the role of electrode geometry and voltage in shaping the electric field, impacting fiber properties. The study introduces a novel, in-house method for producing highly aligned nanofibers and provides insights into optimizing electrospinning parameters for enhanced fiber properties. A testing protocol is devised to minimize surface damage when conducting mechanical tests on nanofiber films, employing a dynamic mechanical analyzer (DMA). Mechanical testing demonstrated the correlation between alignment and tensile strength. Overall, this research contributes valuable insights for tailoring electrospinning processes for tissue engineering and energy storage. [ABSTRACT FROM AUTHOR]

Thermoplastic (TP) composites, known for their ease of handling, suitability for high production rates, and recyclability, are emerging as a promising alternative to thermoset-based composites. The expected growth in TP-based composites in automotive, sports, and aerospace industries may result in increased post industrial waste. To address this, we repurposed our in-house process scrapped carbon fibre-reinforced polycarbonate tapes into sheet moulding compounds (SMCs) and Hybridised SMCs (Hy-SMCs) using compression moulding. In Hy-SMCs, the top and bottom layers were unidirectional tapes, while the core section had randomly oriented platelets in a 50:50 ratio. Our evaluation included qualitative and thermo-mechanical standard tests. The incorporation of unidirectional tapes in Hy-SMCs significantly improved the tensile and flexural properties of SMCs. Specifically, these enhancements resulted in an impressive 81 to 85% increase in mechanical strength compared to the standard aluminium grade. Additionally, Hy-SMCs exhibited a 120 to 130% increase in tensile and flexural properties compared to SMCs. Fractography revealed a complex relation between fractured surfaces, with multimode failures in both SMCs and Hy-SMCs. Also, the non-destructive evaluation showed platelet reorientation during consolidation and localised voids with increased specimen thickness.

For a hygiene paper such as tissue and towel, strength, softness, and absorbency are known as attributes that a user is looking for. It is proposed here that purchasing decisions are likely to be influenced by in-use experiences, which may be quite different from the physical properties measured with current standardized tests. There have been continuous efforts on developing physical test methods to replace subjective in-use tests because the benefits of the former are too significant to be overlooked. This paper considered some in-use test methods for paper towel products that can be carried out by panel members quickly in the course of sensory panel testing. In addition, laboratory tests were developed in an attempt to quantify such input. The sensory panel testing showed that (wet) strength and absorbency were the key contributions to the performance of paper towels. Softness did not show any significant contribution to it. Wet strength showed a high correlation with absorbency. The (wet) ball burst strength had the highest correlation with the in-use strength. Although both the tensile strength and the ball burst strength had a high correlation with preference, the ball burst tester is preferred because more reproducible and simpler to operate.

In order to improve the impact toughness of polyamide 1012 (PA1012) by reducing the amount of hydrogen bonding resulting from PA1012 itself, 3-pentadecylphenol (PDP) was considered to be added into PA1012 using melting extrusion. The hydrogen bonding interaction between PA1012 and PDP was characterized by Fourier transform infrared spectroscopy (FTIR) and nuclear magnetic resonance (NMR). The effects of PDP on the crystallization, melting process, and mechanical behavior of PA1012 were tested in detail. The results show that the PDP can reduce the temperature of PA1012 crystallization and melting but it can significantly improve elongation at break and impact toughness. The notched impact strength of the PA1012/PDP composites containing 20 wt% PDP reached to 70.6 kJ·m–2, which is about seven times that of the neat PA1012. The effects of PDP on PA1012 properties is ascribed to hydrogen bonding interaction between hydrogen bonding between phenol hydroxyl groups and amino groups on PA1012 chains. The deduction was also verified by adding acetylated 3-pentadecylphenol (APDP) to modify PA1012. It is believed the research will open up new prospects for the wide application of PA1012 toughening.

This paper presents a study regarding the obtaining, characterizing and mechanically testing a new laminar composite material, consisting of epoxy resin reinforced with basalt plain fabric. The composites were obtained by manual lay-up, cross-link stage being developed by pressure molding in a hydraulic press. Rectangular plates were obtained and cut into samples with specific shapes, for the mechanical tests (tensile, three-point bending and compression). After testing, the fracture zone was analyzed using optical microscopy to observe the behavior of the composite following the mechanical stresses applied (fracture mechanism, voids presence and fiber delamination identification). Due to the low costs and non-hazardous nature, basalt fibers can be a serious competitor in the production of laminar composites that could successfully replace ordinary glass fiber composites. The mechanical properties in tensile, three-point bending, and compression of epoxy-resin-impregnated basalt fiber composites are comparable and even exceed those of widely used epoxy-resin-impregnated fiberglass composites.

Zinc complexes have a considerable impact on human health and the environment, especially on aquatic wildlife. One of the primary sources of zinc release to the environment is worn rubber particles from tires. The environmental footprint of zinc oxide (ZnO) during production, use, and landfilling has prompted researchers to reduce its use in rubber formulations due to ecological and economic concerns. In this study, composite ZnO materials where ZnO particles are coated on precipitated calcium carbonate (CaCO3) are used in styrene butadiene rubber/butadiene rubber (SBR/BR) compounds, and their performance is compared with white seal ZnO and active ZnO. Trial compounds are prepared on a laboratory scale using composite ZnO materials with ZnO:CaCO3 ratios of 40:60, 60:40, and 90:10, and control compounds with white seal and active ZnO. All compounds are tested to evaluate their curing and physico-mechanical properties. It is observed that the surface area of ZnO plays an essential role in crosslink density and, hence, compound performance. Trial materials have no negative effect on the curing and mechanical properties of the compounds. Thus, it is concluded that composite ZnO materials can be used as alternatives to both white seal ZnO and active ZnO. They have environmental and economic advantages due to their lower ZnO content. The compound recipe has the potential to be used for tire tread compounds.

One of the useful features of 3D-printed specimens of recycled polyethylene terephthalate glycol (R-PETG) is the ability to repetitively develop free recovery as well as the work-generating, shape-memory effect. This behavior is enabled by the R-PETG's capacity to stiffen during cooling, thus allowing for a new temporary shape to be induced. Aiming to devise an explanation for the polymer's stiffening, in this study, the variation in some of the R-PETG's parameters during cooling are emphasized and discussed. The evolution of an R-PETG filament's shape was monitored during room-temperature-bending heating–cooling cycles. Straight-shape recovery and the complete loss of stiffness were observed at the start and the end of heating, respectively, followed by the forced straightening of the filament, performed by the operator, around 40 °C, during cooling. The tests performed by dynamic mechanical analysis disclosed the rise of the storage modulus (E') after 100 °C heating followed by either liquid-nitrogen- or air-cooling to room temperature, in such a way that E' was always larger after cooling than initially. Static tests emphasized a peculiar stress variation during a heating–cooling cycle applied in air, within the heating chamber of the tensile testing machine. Tensile-failure tests were performed at −10 °C at a rate of 100 mm/min, with specimens printed at various deposition directions between 10 and 40° to the transversal direction. The specimens printed at 40°, which had the largest ultimate strains, were broken with tensile rates between 100 and 500 mm/min. Deformation rate increase favored the shift from crazing to delamination failure modes. The correlation between the structural changes, the sharp E' increase on heating, and the stiffening induced by cooling represents a novel approach that enables the use of 3D-printed R-PETG for the fabrication of the active parts of low-priced lightweight resettable actuators. [ABSTRACT FROM AUTHOR]

Purpose: Quantifying the stability of individual plants or their contribution to soil reinforcement against erosion or landslides requires an understanding of the tensile properties of their roots. This work developed a new analytical model to understand the tensile stress–strain behaviour of a single root axis, which is the first to incorporating root anatomical features, in order to reduce the existing uncertainty in predictions. Methods: The root was modelled as a linear elastic stele connected to a surrounding linear elastic cortex by means of a linear elastic stele–cortex interface. By solving for force equilibrium, an analytical solution for the full tensile stress–strain behaviour — including any intermediate brittle failures of the stele, cortex and/or interface — was obtained. This model was compared to tensile tests and laser ablation tomography for maize roots. Results: The new modelling approach demonstrated that the root tensile strength is fully determined by the strength of the stele alone, which was an order of magnitude larger than that of the cortex while also 3–4 times stiffer. The reduction in root stiffness beyond the yield point was linked to continuing fracturing of the cortex and debonding along the stele–cortex interface. A larger proportion of the variation in experimentally measured biomechanical characteristics could be explained compared to root diameter power-law fitting methods typically applied in the literature. Conclusion: Stele and cortex biomechanical properties are substantially different, affecting the tensile behaviour of plant roots. Accounting for these anatomical traits increased the accuracy root biomechanical properties from tensile tests. [ABSTRACT FROM AUTHOR]

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During service, shoe-braked railway wheel steels are often subjected to a severe thermal cycle. Therefore, understanding the evolution of the microstructure and the resulting changes in mechanical properties during service is fundamental in the choice of steel. In previous research, the effects of the thermal loading on the microstructure and mechanical properties of five different steels for railway wheels (ER7, HYPERLOS®, Class B, SANDLOS® and Class C) were investigated by hardness, tensile and toughness tests, in the as-supplied condition and after different heat treatments designed to replicate the modification of the microstructure due to braking. In this paper, the tensile work hardening behavior was studied by interpolating the tensile flow curves with the constitutive equation related to the dislocation density proposed by Voce, which correlates the Voce equation parameters with the microstructural features of metallic materials. The work hardening analysis revealed that there is a good correlation between the Voce parameters and the microstructure of the five steels in as-supplied condition and after heat treatments. An interesting correlation was found between Voce parameters and apparent fracture toughness. After heat treatments at 700 °C and 750 °C the properties of the steels decreased, which was consistent with the evolution of the microstructure. However, after exposure at 970 °C with subsequent cooling in air, Class C steel appears to have a microstructure similar to the original microstructure, with tensile and toughness properties very similar to the as-supplied condition, demonstrating better microstructural stability compared to steels ER7, HYPERLOS®, Class B and SANDLOS®. [ABSTRACT FROM AUTHOR]

Tensile testing (aka tension testing) is a widely employed mechanical testing technique for analyzing materials' properties and behavior under applied stress. Tensile testing plays a pivotal role in helping engineers to make informed decision about material selection and usage. Despite its importance, there is a limited numbers of studies that explored the potential of AI techniques for real time monitoring and material behavior prediction in tensile testing. To this end, this work presents a deep learning model designed to predict the material's condition throughout tensile testing and provide an early warning prior to fracture. By leveraging a comprehensive dataset of tension test video samples, the proposed model utilizes both convolution and recurrent neural networks to extract pertinent spatial and temporal visual features, thereby predicting the frames at which material deformation and fracture occur. The evaluation results of our research showed that the proposed model achieved a predictive ability with an F1-score of 97%, on average. The implications of our research are significant for industries and researchers in the field of materials science and engineering. By accurately predicting material status, our model enables autonomous, real time analysis of material behavior during tensile testing, leading to better time and cost efficiency in various applications. [ABSTRACT FROM AUTHOR]

This study explores the mechanical properties of Glass Fiber-Reinforced Polymer (GFRP), a high-performance composite material, focusing on how varying diameters affect its tensile strength, modulus, and elongation. Experimental data obtained from three sets of tensile tests on 10, 12, and 25 mm bars helped establish a stress–strain relationship for GFRP reinforcements, considering diameter changes, and a formula for calculating the ultimate tensile strength based on diameter. Utilizing the weakest chain theory and the Weibull distribution, the research found that GFRP's tensile strength diminished with increased diameter, while the elastic modulus behaves oppositely. The analysis, grounded in the weakest chain theory, identifies the specimen's effective volume as a critical factor in the size effect of GFRP bars. Moreover, the study proves a significant size effect on GFRP's tensile properties, validating the theory's application in predicting the strength of GFRP bars of varying sizes and recommending a specimen length range of 30–40 times its diameter for standardization purposes. [ABSTRACT FROM AUTHOR]

Objectives: To investigate whether acid etch contamination of silane-treated composite influenced repair bond strength and whether silane contamination on dentin influenced composite bond strength to dentin. Materials and methods: Forty composite blocks stored in water for 4 weeks were divided into four groups. Specimens in groups 1–3 were coated with Bis-Silane and contaminated with acid etch + water spray (group 1) or water spray (group 2). Group 3 was not contaminated. Group 4 was untreated. The occlusal third of 60 third molars was cut off, ground flat, and divided into three groups. After etching, the surfaces in groups A and B were contaminated with Bis-silane. The contaminated surfaces in group A were re-etched. Each composite repair group and composite-dentin group was divided into two subgroups receiving Adper Scotchbond 1 XT or Clearfil SE Bond 2 adhesives followed by a composite build up. After ageing for 3 months, specimens were sectioned into 1.1 mm × 1.1 mm rods for tensile testing and strength calculated at fracture. The fracture was examined using microscope. Results: Bis-Silane surface treatment increased the repair bond strength. Contamination with acid reduced the strength of the repair bond. Similar results were obtained for both adhesives. Tooth surface contamination with silane reduced the bond strength between dentin and composite. Additional acid etching or water spray on silane contaminated dentin did not influence the weakened bond strength. Most fractures were adhesive type. Conclusions: Silane contamination on etched dentin and acid etch contamination on silanized composite surfaces significantly reduced tensile bond strength.

This data article presents a set of primary, analyzed, and digitalized mechanical testing datasets for nine copper alloys. The mechanical testing methods including the Brinell and Vickers hardness, tensile, stress relaxation, and low-cycle fatigue (LCF) testing were performed according to the DIN/ISO standards. The obtained primary testing data (84 files) mainly contain the raw measured data along with the testing metadata of the processes, materials, and testing machines. Five secondary datasets were also provided for each testing method by collecting the main meta- and measurement data from the primary data and the outputs of data analyses. These datasets give materials scientists beneficial data for comparative material selection analyses by clarifying the wide range of mechanical properties of copper alloys, including Brinell and Vickers hardness, yield and tensile strengths, elongation, reduction of area, relaxed and residual stresses, and LCF fatigue life. Furthermore, both the primary and secondary datasets were digitalized by the approach introduced in the research article entitled “Toward a digital materials mechanical testing lab” [1]. The resulting open-linked data are the machine-processable semantic descriptions of data and their generation processes and can be easily queried by semantic searches to enable advanced data-driven materials research.

Graphene oxide (GO) nanoplatelets can be used to reinforce neat resin or the matrix phase of fiber composites for improved mechanical properties. Although the oxygen content levels in GO and reduced graphene oxide (rGO) strongly influence the interface with the polymer, experimental-based optimization of the oxygen content for enhanced composite properties is difficult and time-consuming. Fortunately, molecular dynamics (MD) simulation can be used to efficiently predict the interfacial properties of composite on the molecular level and provide physical insight into the effect of the oxygen content of rGO. In this study, MD is used to predict the elastic properties of rGO/epoxy interfaces and the corresponding interfacial shear strength (IFSS) for different oxygen content levels. The results indicate that increasing levels of oxygen in rGO results in interfaces with a reduced in-plane elastic modulus but a substantially higher IFSS. These results are important for the design of rGO/epoxy composites for specific engineering applications.

Manufacturing composites using natural fibers support the development of more ecologically friendly applications in many industrial areas, including sports equipment, wind turbine blades, construction materials, packaging, medical devices, and prosthetics. To investigate the tests’ number (N) impact on the fibers’ tensile behavior, newly developed fibers from the Strelitzia juncea (SJ) plant are being studied for their mechanical properties using various statistical laws. This study aims to assess the SJ fibers’ performance with a gauge length of 50 mm under quasi-static stress conditions. 150 SJ fibers were tensile tested in five groups (30, 60, 90, 120, and 150) to determine the N impact on the fibers’ tensile strength, break deformation, and Young’s modulus. Weibull and log-normal distributions were used to study statistically the mechanical properties results, and their dispersion was investigated and quantified using least squares and maximum likelihood prediction model with a confidence level of 95%.

ABSTRACTTensile testing is the most common method to investigate natural fibers. The fibers’ mechanical behavior can be considered non-linear and is influenced by viscoelasticity, plasticity, and environmental conditions. Very often such fibers are tested by gluing them with an adhesive onto a sample holder. Such a system consisting of a polymeric sample holder, adhesive, and natural fiber is complex and there is a risk that the mechanical response measured is a mix of the different contributions of those components. In this work, the key components for tensile testing of natural fibers ‒ sample holder and adhesive ‒ are investigated, to determine their influence on the measurement results. In order to isolate the influence of the measurement setup, the natural fiber is replaced with a platinum wire, which is purely linear-elastic. Hence all non-linear contributions from sample holder or adhesive can be identified. The main influence factor on the results was the glue used for fixating the fiber on the sample holder. Epoxy resin was found to be best suited. Taking these findings into account, a series of tensile tests was performed on cellulose-based natural fibers for demonstration but is applicable to any natural fiber.

AbstractThe design and performance evaluation of a 30 kN mechanical testing machine with capacities for room temperature and hot tensile and compression testing was performed. The design philosophy, material selection, and construction strategy were based on the functions and properties of the materials and control systems, local availability, cost considerations, and ease of assembly and decoupling of the parts. Simulation studies were conducted to optimize the design, loading capacity, and specimen dimensions and configurations. The loading mechanism was by a hydraulic system and a loading frame was constructed to house the hydraulic loading, specimen holding, and heating band systems. Testing to ascertain the performance of the machine using aluminum 6063 alloy samples was preceded by load cell and extensometer calibration of the machine. From the performance evaluation, the UTS and percent elongation values for room temperature (25 °C) tensile test (446–454 MPa and 28.3–28.7%) hot tensile tests at 250 °C (232–233 MPa and 36.3–36.7%), room temperature compression test (439–518 MPa and 32.7–33%), and hot compression test at 250 °C (226–233 MPa and 34–35%), were found to be largely reproducible and values were within the range reported in literature for Aluminum 6063 alloy. The softening mechanisms dominant at elevated temperatures ensured that the strain hardening effect was minimal, which is the reason for the superior percent elongation but lower UTS values for tensile and compression tests performed at 250 °C.

Ion beam implantations are widely performed to understand the effects of irradiation-induced displacement damage on nuclear structural materials. However, the volume of material that can be investigated is often limited by the maximum energies of accelerator facilitates, leading to a limitation in the thickness of samples whose mechanical properties can be evaluated. The Lawrence Berkeley National Laboratory's 88-Inch Cyclotron offers a wide range of ions and energies, allowing for material ion implantations at larger scales than typical. Four HT-9 SS-J-geometry tensile specimens were polished and then irradiated with deuterons at the 88-Inch Cyclotron to doses of approximately 0.2 dpa prior to small scale tensile testing. The results from this study show irradiation hardening characterized by the tensile test results and black dot irradiation defects. Additionally, a comprehensive look at low temperature irradiations of high-Cr F/M steels is presented and our results show agreement with the available data.

• We present a shortcut in the compositional analysis of plastic waste. • The separation system's influence on the homogeneity and performance is examined. • Both HDPE samples display good material performance and a homogeneous composition. • PP and LDPE from post source separation display slightly more heterogeneity. • Multivariate FTIR data evaluation is a fast and informative analysis method. Whether plastic packaging waste is disposed of in different bins (source separation, S) or in a single bin (post source separation, P) is generally assumed to impact the waste stream's quality. To elucidate this question, we evaluated the quality of LDPE, HDPE, and PP plastic waste from both separation systems (S and P) through a concise analytical strategy. The materials received similar treatment after collection (e.g., washing, NIR-sorting). A multivariate approach to ATR-FTIR spectroscopy was developed to assess their material composition and the effect of washing. Results were complemented by TGA, DSC, and py-GC/MS analysis. The material performance was investigated by a lab-scale extrusion and granulation, followed by an assessment of the mechanical properties and the melt volume rate. Our study reveals the HDPE materials to be of good quality, regardless of their source. For LDPE and PP, the P-materials are fractionally more contaminated after washing. Both PP-materials display poor material performance with highly fluctuating elongations-at-break (between 30 % and 380 %). S-LDPE was found to contain more polymeric impurities than P-LDPE. We conclude that the quality depends strongly on the material type and on the treatment after collection (washing, sorting). The multivariate approach to FTIR data evaluation we propose aims at simplifying the quality evaluation of polyolefin waste plastics and may serve as a basis for future work in this field. [ABSTRACT FROM AUTHOR]

Additive manufacturing, with its fast development and application of polymeric materials, led to the wide utilization of polylactic acid (PLA) materials. As a biodegradable and biocompatible aliphatic polyester, produced from renewable sources, PLA is widely used in different sectors, from industry to medicine and science. The aim of this research is to determine the differences between two forms of the PLA material, i.e., fused deposition modeling (FDM) printed filament and digital light processing (DLP) printed resin, followed by aging due to environmental and hygiene maintenance conditions for a period of two months. Specimens underwent 3D scanning, tensile testing, and Fourier transform infrared (FTIR) spectrometry to obtain insights into the material changes that occurred. Two-way Analysis of Variance (ANOVA) statistical analysis was subsequently carried out to determine the statistical significance of the determined changes. Significant impairment can be observed in the dimensional accuracies between both materials, whether they are non-aged or aged. The mechanical properties fluctuated for aged FDM specimens: 15% for ultimate tensile stress, 15% for elongation at yield, and 12% for elastic modulus. Regarding the DLP aged specimens, the UTS decreased by 61%, elongation at yield by around 61%, and elastic modulus by 62%. According to the FTIR spectral analysis, the PLA materials degraded, especially in the case of resin specimens. Aging also showed a significant influence on the elastic modulus, ultimate tensile stress, elongation at yield, elongation at break, and toughness of both materials, which was statistically shown by means of a two-way ANOVA test. The data collected in this research give a better understanding of the underlying aging mechanism of PLA materials. [ABSTRACT FROM AUTHOR]

Owing to its reflectivity, Copper manufacturing has always been challenging through laser-based additive manufacturing. In this study, we demonstrate additive/bulk manufacturing of copper using high velocity air fuel (HVAF) spray technology, an emerging variant in the thermal spray family. Rapid deposition of millimeter scale copper parts with good mechanical integrity and decent ductility, comparable to that of cold spray, has been shown feasible. The mechanical properties measured along different built directions showed no significance to be considered anisotropic. Electron backscattered diffraction analysis revealed the possibility of developing favorable bimodal grain distribution with a high volume fraction of ultrafine grains (>50%). However, the intersplat porosities and continuous pores were found to be detrimental despite the low overall porosity. HVAF technology demonstrates great potential and appears to be a promising process methodology for bulk/additive manufacturing of metals with a rapid production rate. [ABSTRACT FROM AUTHOR]

This paper presents a study regarding the obtaining, characterizing and mechanically testing a new laminar composite material, consisting of epoxy resin reinforced with basalt plain fabric. The composites were obtained by manual lay-up, cross-link stage being developed by pressure molding in a hydraulic press. Rectangular plates were obtained and cut into samples with specific shapes, for the mechanical tests (tensile, three-point bending and compression). After testing, the fracture zone was analyzed using optical microscopy to observe the behavior of the composite following the mechanical stresses applied (fracture mechanism, voids presence and fiber delamination identification). Due to the low costs and non-hazardous nature, basalt fibers can be a serious competitor in the production of laminar composites that could successfully replace ordinary glass fiber composites. The mechanical properties in tensile, three-point bending, and compression of epoxy-resin-impregnated basalt fiber composites are comparable and even exceed those of widely used epoxy-resin-impregnated fiberglass composites. [ABSTRACT FROM AUTHOR]

Explore the intriguing world of natural fibers, where Syagrus Romanzoffiana (SR) fibers out as a viable alternative to synthetic and glass fibers in composite materials. Dive into the eco-friendly attraction of SR fibers, which are renowned for their natural degradation and ecologically favorable properties. This novel work investigates the performance characterization of 40 mm gauge-length (GL) SR fibers under quasi-static pressures using rigorous tensile testing. The mystery develops when 200 fibers are examined in seven different test groups, revealing the effect of test quantity (N) on tensile strength, Young's modulus, and fracture strain. Given the intrinsic diversity of natural fibers, the study applies strong statistical approaches such as least squares (LS) and maximum likelihood (ML) estimations, as well as two- and three-parameter Weibull distributions. Witness the thorough dispersion and probability analysis, which culminates in an enthralling one-factor analysis of variance (ANOVA) across the seven test groups (N = 30, 60, 90, 120, 150, 180 and 200) for each tensile strength characteristic. Join us on this scientific trip as we uncover the mysteries and promise of Syagrus Romanzoffiana fibers to shape the future of composite materials. [ABSTRACT FROM AUTHOR]

Continuous fiber reinforced thermoplastics (cFRTP) are one of the most promising lightweight materials. For their use in structural components, reproducible and comparable material values have to be evaluated, especially at high strain rates. Due to their high stiffness and outstanding strength properties, the evaluation of the material behavior at high strain rates is complex. In the presented work, a new tensile specimen geometry for strain rate testing is virtually optimized using a metamodel approach with an artificial neural network. The final specimen design is experimentally validated and compared with rectangular specimen results for a carbon fiber reinforced polycarbonate (CF-PC). The optimized specimen geometry leads to 100% valid test results in experimental validation of cross-ply laminates and reaches 9% higher tensile strength values than the rectangle geometry with applied end tabs at a strain rate of 40 s−1. Through the optimization, comparable material parameters can be efficiently generated for a successful cFRTP strain rate characterization. [ABSTRACT FROM AUTHOR]

Additive technologies are continually evolving and are crucial in numerous industries, including medical, aerospace, and automotive, but they can also play an important role in the prototyping phase. Due to additive manufacturing, amateurs and enthusiasts can construct simple projects as well as large projects with specialized usage in specific applications. When it comes to complex pieces, traditional manufacturing technologies such as milling, chipping, drilling, and so on have specific constraints, often need even additional production processes to complete the item. All of these constraints can be solved with additive technologies. This work investigates Fused Deposit Modeling (FDM) printing of many specimens with varying properties in order to analyze PLA (Poly Lactic Acid) material behavior following tensile testing. The collected findings will be analyzed in order to determine the specimens with the most significant behavior according on the modified parameters. [ABSTRACT FROM AUTHOR]

Magnesium-based alloys show significant promise for widespread applications owing to their lightweight nature and improved mechanical properties achieved through grain refinement via hot rolling. This investigation focuses on Mg-xAl-yCa-zMn (AXM alloys), pre-heated to temperatures of 350, 400, and 450 °C and processed via both single-pass differential speed rolling (DSR) and conventional rolling (CR). The key findings reveal the interplay between processing temperature, strain rate during single-pass rolling, and an innovative approach for incorporating varying amounts of Ca, influencing grain size, quantity of dynamic recrystallization (DRX) grains, and overall mechanical properties, including strength and ductility. A noteworthy observation is the positive correlation between an increase in the total reduction during hot rolling and a higher fraction of DRXed grains. This leads to a significant reduction in average grain size, diminishing from 60.3 ± 54.3 μm to 19.5 ± 14.2 μm at 40%, nearly a third the size of T4 grains (the initial homogenized microstructure of the AXM alloys). The resultant material strength experiences a doubling from an average of 125 ± 10.2 MPa (T4) to 260 ± 25.8 MPa (DSR rolled at 40%) for the AXM alloys with potential improvement in the ductility depending on rolling speed conditions. This study also aims to analyze the combination of rolling temperature, rolling speed, thickness reduction, speed difference and Ca content implemented across a wide range of temperatures and strain rates to provide a holistic approach to the processing parameters affecting the microstructure and mechanical properties of AXM alloys. Furthermore, this study provides a deeper understanding of DRX mechanisms, including continuous DRX (CDRX), discontinuous DRX (DDRX), and twinning induced DRX (TDRX), while each of these mechanisms plays a distinct role in the overall enhancement of formability and performance of magnesium alloys. [ABSTRACT FROM AUTHOR]

In this study, two variations of magnetorheological elastomer (MRE) tensile specimens were fabricated, differing in their isotropic and anisotropic configurations. The isotropic MRE exhibited randomly dispersed carbonyl iron particle (CIP), whereas the anisotropic featured longitudinally aligned CIP particles along the gauge length of the tensile sample. The formation of the anisotropic MRE involved utilizing an electromagnetic curing chamber, which facilitated the alignment of CIP particles during the elastomer curing process. A mold was specifically designed to produce samples conforming to the dimensions outlined in ASTMD412-F. Subsequently, a Finite Element Method Magnetics (FEMM) analysis was conducted to examine the magnetic flux within the curing device for the anisotropic MRE. Uniaxial tensile tests were conducted on both MRE types, both in the absence and presence of a 30 mT magnetic field applied transversely to the direction of CIP alignment. Results indicated that without a magnetic field, the anisotropic sample exhibited a slightly higher tensile strength, lower elongation, and higher modulus at 100% strain. However, when a magnetic field was introduced, the isotropic sample demonstrated a more pronounced increase in tensile strength, showing an 18.4% improvement compared to the 5.6% increase observed in the anisotropic sample. Similar trends were observed in the reduction of elongation, with a 14% decrease for isotropic and a 7% decrease for anisotropic samples. Additionally, the data on modulus at a 100% strain revealed a 22.3% increase in stiffness for the isotropic sample, while the anisotropic sample showed a 10.6% increase. [ABSTRACT FROM AUTHOR]

As a wind blade is getting larger, its structural behavior becomes more complex and thus the risk of blade structural failure becomes higher. Generally, structural integrity is proved through blade testing with contact measurement devices such as strain gauges. However, contact measurement can only measure the physical quantities from installation points and requires lengthy cables to transmit the electrical signals to a data acquisition system, which can cause signal noise and add unnecessary weight. Recently, noncontact measurement techniques such as digital image correlation (DIC) have been widely used in various industries to process images captured from cameras and generate full-field strains and displacements without any mechanical connections such as cables. In this study, the application of three-dimensional DIC to wind blades was investigated; in addition, the material properties of glass-fiber-reinforced plastics used in blades for the measurement of the first frequency were also studied. Tensile testing was performed using coupons equipped with strain gauges and speckle patterns. In addition, a small blade from a 10 kW wind turbine was utilized to measure the first flapwise frequency using DIC and modal tests; the results showed a 2.1% difference between the two different measurements. This research showed that the DIC technique could be an alternative replacement for the traditional measurement technique upon further validation tests. [ABSTRACT FROM AUTHOR]

Background: Surgical repair of muscle lacerations is the standard of care to restore function. Compared to non-surgically repaired lacerations, surgical repairs have been shown to heal faster and have higher strength return and lower incidence of hematomas. Multiple techniques have been reported to repair muscle lacerations. There are many factors to consider in choosing a technique for muscle belly repair including scar tissue formation, length of immobilization, strength of repair, and suture pullout. An ideal repair method has not yet been clearly identified; therefore, the purpose of this review is to evaluate the existing literature on various repair methods and the methods used to test them. Methods: Using the PRISMA-ScR framework, a scoping review was performed to identify biomechanical studies that examined the strength and efficacy of muscle belly repair techniques. PubMed, Web of Science, and Scopus were searched to locate relevant studies. Results: Nine original studies which met inclusion criteria were selected for final review. Six studies evaluated specific suture techniques, while the remaining three studies evaluated, inclusion of epimysium in the repair, repair of the epimysium versus perimysium, and porcine versus bovine skeletal muscle biomechanical properties. While the six studies evaluating suture techniques tested overlapping suture types, they varied in preload and peak load values and the type of suture used, yielding heterogenous data. The compiled data did not support one method being the optimal repair choice. Conclusions: Existing literature evaluating the mechanics of muscle repair is limited by a lack of standardization. The included studies suggest that using sutures which incorporate the epimysium or using a combination of sutures that anchor the core of the muscle belly and encompass the perimeter may yield more robust repairs than other techniques. However, further research using comparable experimental conditions is necessary to identify an ideal muscle belly repair technique. Level of evidence: Not gradable. [ABSTRACT FROM AUTHOR]

This study investigates the influence of surface finish and post-processing conditions on the mechanical properties of 17-4 PH stainless steel (SS) produced using the atomic diffusion additive manufacturing process (ADAM). Diverse sample orientations, including horizontal (0°), 30°, 60°, and vertical (90°), were examined, with selected samples undergoing post-processing through machining, polishing, and heat treatment. Tensile strength testing, surface roughness measurement, and hardness measurement were conducted to assess the effect of surface finish conditions and post-processing on mechanical properties. The results reveal significant variations in the tensile strength of the samples based on the build orientation (183.5 to 1034.5 MPa), and subsequent machining. Notably, post-built machining is found to enhance both the absolute ultimate tensile strength (UTS) and the isotropy of the material. Further improvements are attainable through heat treatment. A microstructure analysis, in conjunction with tensile testing outcomes, demonstrates the potential for refining the properties of ADAM-printed samples through suitable machining, heat treatment, and geometry modifications. This study identifies avenues for ongoing process development and outlines possibilities for enhancing mechanical properties of additive manufactured parts, particularly through ADAM process. [ABSTRACT FROM AUTHOR]

Osteosynthesis in fracture treatment typically uses hardware that remains in the patient's body, which brings a permanent risk of negative side effects such as foreign body reactions or chronic inflammation. Bioabsorbable materials, however, can degrade and slowly be replaced by autologous bone tissue. A suitable material is requested to offer great biocompatibility alongside excellent mechanical properties and a reasonable corrosion rate. Zinc–silver alloys provide these characteristics, which makes them a promising candidate for research. This study investigated the aptitude as a bioabsorbable implant of a novel zinc–silver alloy containing 3.3 wt% silver (ZnAg3). Here, the tensile strength as well as the corrosion rate in PBS solution (phosphate buffered solution) of ZnAg3 were assessed. Furthermore, shear tests, including fatigue and quasi-static testing, were conducted with ZnAg3 and magnesium pins (MAGNEZIX®, Syntellix AG, Hannover, Germany), which are already in clinical use. The detected corrosion rate of 0.10 mm/year for ZnAg3 was within the proposed range for bioabsorbable implants. With a tensile strength of 237.5 ± 2.12 MPa and a shear strength of 144.8 ± 13.2 N, ZnAg3 satisfied the mechanical requirements for bioabsorbable implants. The fatigue testing did not show any significant difference between ZnAg3 and magnesium pins, whereas both materials withstood the cyclic loading. Thus, the results support the assumption that ZnAg3 is qualified for further investigation. [ABSTRACT FROM AUTHOR]

Paper is susceptible to chemical degradation through hydrolysis and oxidation, resulting in embrittlement and failure. Understanding the embrittlement process is important to ensure the preservation and longevity of historical paper-based documents. However, the complex and architectured paper microstructure is a major challenge for fully understanding this process. Two papers with different microstructures were artificially aged under hydrolytic and oxidative exposure conditions, and the consequences of ageing were studied. The fibre embrittlement, the fibre–fibre bonds deterioration, and the evolution of paper microstructure upon ageing are evaluated through macroscopic and localised mechanical tests, as well as through morphological observations at the microscopic scale. It was concluded, from the different tests in the two principal orientations of the paper, that fibre embrittlement plays a more significant role in the embrittlement process than fibre–fibre bonds deterioration. Specifically, the cellulose chain scissions led to fibre embrittlement, irrespective of the oxidative or hydrolytic nature of the chemical degradation mechanism. Furthermore, we identify a critical degree of polymerisation for cellulose (DPc ~ 750) below which the evolution of mechanical properties accelerates significantly, regardless of the type of mechanical testing performed. Fibre analysis suggests that the decline in fibre resistance results in fractures occurring under stress at weak points of the fibres, such as kinks or twists. [ABSTRACT FROM AUTHOR]

Bamboo, being a natural and sustainable construction material with remarkable mechanical properties, warrants comprehensive study for efficient and safe engineering applications. However, there is limited research on its behavior, particularly in Thailand. Therefore, this paper investigates 102 Thai bamboo specimens from three species (Dendrocalamus sericeus, Phyllostachys makinoi, and Thyrsostachys oliveri) and two node conditions to examine their tensile mechanical properties and develop a bamboo constitutive model for finite element analysis. The test results indicate that specimens with nodes exhibit lower maximum tensile strength compared to those without nodes, with differences of approximately 86.68 %, 45.54 %, and 50.35 % for Dendrocalamus sericeus, Phyllostachys makinoi, and Thyrsostachys oliveri bamboo, respectively. Statistical methods were employed to gather data and predict tensile stress and strain at the specimen’s fracture point. A displacement-based formula was utilized to formulate the constitutive law for the proposed bamboo bar model. The accuracy and capability of the proposed model were verified through three numerical simulations: a convergence study, validation with experimental data, and analysis of bamboo applications in structural engineering. The results demonstrate good accuracy and capability, providing up-to-date local bamboo testing results in Thailand for future engineering applications.

A 316 austenitic stainless-steel alloy, with modified alloy composition, manufactured by laser powder bed fusion (L-PBF) has been investigated. The modification of the alloy composition included addition of niobium (Nb), tungsten (W) and copper (Cu), together with a reduction in the amount of molybdenum (Mo) and an increased amount of carbon (C). To find suitable process parameters, a parameter study by varying laser power, hatch distance and scan speed was performed, centered on typical parameters used for normal 316 L. As-built material from a selected parameter configuration was then subjected to different stress relief annealing heat treatments and ageing heat treatments. The effectiveness of the stress annealing was ranked using a deformation-based method. Microstructural characterization, hardness and room temperature tensile testing were done to evaluate the effect of stress relief and aging heat treatments.It was found that a higher volumetric energy was needed to build dense material, about ∼50 % higher compared to the volumetric energy input for normal 316 L. A subsequent aging heat treatment at 725 °C for 3 h increased the strength and hardness of the material. A reinforcement of the cellular microstructure by precipitation of carbides in between the cells is believed to be the main reason for this. To completely alleviate the residual stresses it was necessary to carry out a stress relief annealing process at 950 °C, which resulted in a removal of the cellular structure and a lower strength material.

Composite materials are of increasing interest in aircraft and spacecraft structures, and carbon fiber reinforced polymers (CFRP) have emerged as materials meeting quality standards for structural applications in the aircraft industry. Despite their high mechanical properties, CFRPs are associated with high production costs. Building on recent research by the authors, this paper investigates the use of ply-level hybridization to reduce manufacturing costs while maintaining the mechanical performance of the manufactured material. Focusing on the causes of nonlinear response under off-axis tensile loading, the paper involves cyclic load-unload (LU) tensile tests conducted at off-axis angles of 15°, 30°, and 45° to predict mechanical characteristics and damage evolution. Residual strains are directly extracted from load-unload stress-strain responses. Three distinct methods for estimating cycle modulus are employed and compared for damage variable formulation. The research findings reveal dependencies of both the damage variable and residual strains on the off-axis angle. Furthermore, the method used to assess the modulus during cycling loading significantly influences the damage variable estimation. Encouragingly, the hybrid laminates exhibit reduced internal damage and matrix plasticity compared to reference counterparts, indicating a positive effect on the mechanical performances of hybridized CFRPs in addition to the cost reduction.