Tensile Mechanical Properties Research Articles

Digital Light Processing Route for 3D Printing of Acrylate-Modified PLA/Lignin Blends: Microstructure and Mechanical Performance

In this study, digital light processing (DLP) was utilized to generate 3D-printed blends composed of photosensitive acrylate-modified polylactic acid (PLA) resin mixed with varying weight ratios of lignin extracted from softwood, typically ranging from 5 wt% to 30 wt%. The microstructure of these 3D-printed blends was examined through X-ray microtomography. Additionally, the tensile mechanical properties of all blends were assessed in relation to the weight ratio and post-curing treatment. The results suggest that post-curing significantly influences the tensile properties of the 3D-printed composites, especially in modulating the brittleness of the prints. Furthermore, an optimal weight ratio was identified to be around 5 wt%, beyond which UV light photopolymerization experiences compromises. These findings regarding acrylate-modified PLA/lignin blends offer a cost-effective alternative for producing 3D-printed bio-sourced components, maintaining technical performance in reasonable-cost, low-temperature 3D printing, and with a low environmental footprint.

Inhomogeneity and anisotropy of Al-Zn-Mg-Cu alloy manufactured by wire arc additive manufacturing: microstructure, mechanical properties, stress corrosion cracking susceptibility

ABSTRACT In this study, Al-Zn-Mg-Cu alloy components were prepared using wire arc additive manufacturing (WAAM). Through multi-scale characterisation technology, performance testing and slow strain rate tensile (SSRT) testing, the microstructure, mechanical properties and stress corrosion cracking (SCC) susceptibility of WAAM Al-Zn-Mg-Cu components were studied, revealing the generation mechanism of inhomogeneity and anisotropy. The results show that with the increase of WAAM thermal cycles, the matrix precipitates (MPs), grain boundary precipitates (GBPs) and precipitation-free zones (PFZ) evolve in different paths and increase to varying degrees, resulting in performance decrease and increase in stress corrosion susceptibility, so the inhomogeneity is mainly attributed to differences in precipitated phases. The Inter-layer inclined to the scanning direction and the Inner-layer inclined to the building direction led to anisotropy in tensile strength and SCC behaviour, so the anisotropy is mainly attributed to the grain orientation and fracture mode.

Quantitative Analysis on Tensile Mechanical Properties and Microscopic Characteristics of Acidified Limestone

Quantitative Analysis on Tensile Mechanical Properties and Microscopic Characteristics of Acidified Limestone

Performance evolution of epoxy adhesive and CFRP-steel epoxy-bonded joints subjected to hygrothermal exposure

Carbon fiber-reinforced polymer (CFRP)-steel epoxy-bonded joints are widely used in civil, mechanical, and railway engineering structures. However, the mechanical and bonding performance of the epoxy adhesive is sensitive to hygrothermal exposure, which may lead to performance degradation of CFRP-steel bonded interfaces. In this study, the performance evolution of epoxy adhesives and CFRP-steel epoxy-bonded joints after hygrothermal exposure was investigated. Three temperature levels (25°C/50°C/75°C) and three hygrothermal exposure time levels (24h/120h/360h) were considered. The dynamic mechanical behavior and tensile properties of the bulk adhesives were studied by dynamic mechanical analysis (DMA) and tensile tests, respectively. Additionally, the mechanical failure properties of the bonded joints, including failure mode, strain distribution, and bond-slip relationship were obtained by tensile tests. The results indicated that the glass transition temperature (GTT) and tensile strength of adhesive J133 are always higher than those of A2014 in all test scenarios. The interface remains the weakest after hygrothermal exposure. After the 50°C hygrothermal exposure, both CFRP-steel joints possess the highest bond strength and interfacial maximum bond stress, which corresponds to their higher adhesive tensile strength at the same temperature. In addition, we also find that both CFRP-steel joints show an increase in bond strength after short-term hygrothermal exposure.

Research on the bending and tensile mechanical properties of ceramic yarns

Research on the bending and tensile mechanical properties of ceramic yarns

Enhanced toughness and ductility of T91 steel after exposure to liquid LBE saturated by oxygen at 350–500 °C

The mechanical tensile properties of T91 steel after being oxidized in liquid LBE saturated by oxygen at 350–500 °C for up to 1000 h are studied. Duplex oxide scales are found on T91 steels after the LBE exposure, and the thickness evolution is revealed. Oxidized T91 steels with surface oxide scale yield enhanced toughness and ductility, which is mainly attributed to the inner oxide layer. We show that the enhancing effect relies on the presence of the oxide scale, not its thickness. The possible enhancing effect of the oxide scale on the toughness of T91 steel by impeding the dislocation from emitting out of the steel surfaces is discussed and qualitatively verified by micro-scale elastoplastic simulations based on a newly proposed discrete dislocation dynamics and peridynamics superposition scheme.

Enhancing Mechanical Properties of Corn Bran Arabinoxylan Films for Sustainable Food Packaging.

Arabinoxylan (AX)-based films can improve the mechanical characteristics of biodegradable materials when utilized for food packaging. However, the mechanical properties of AX films for food packaging applications require thorough investigation to establish their viability. In this study, AX was extracted from corn bran coproducts of dry-milling (DCB), wet-milling (WCB), and dried distiller's grains with solubles (DDGS) using an acid-alkali method. Packaging materials were produced using these AX extracts, each combined with laccase and sorbitol, forming the basis for three different films. These films were then modified by immersing the surface in a lipase-acetate solution. We evaluated their mechanical characteristics, including thickness, tensile properties, tear resistance, and puncture resistance. The thickness and tensile properties of the modified AX films derived from DCB and DDGS showed significant improvements (p < 0.05) compared to the unmodified AX films. In contrast, the modified AX films from WCB showed no significant changes (p > 0.05) in thickness and tensile properties compared to the unmodified WCB AX films. A significant increase in tear resistance (p < 0.05) was observed in all modified AX films after immersion in the lipase-acetate mixture. While puncture resistance was enhanced in the modified AX films, the improvement was not statistically significant (p > 0.05) compared to the unmodified films. The presence of hydroxyl (OH) and carbonyl (CO) groups on the surfaces of AX films from DCB and DDGS, modified by the lipase-acetate solution, suggests excellent biodegradability properties. The modification process positively affected the AX films, rendering them more bendable, flexible, and resistant to deformation when stretched, compared to the unmodified AX films.

Atomic-level analysis of unusual mechanical and failure behaviors in compositionally graded nanowires: A molecular dynamics study

Compositionally graded materials have emerged at the frontier of science involving material science, engineering, physics, and chemistry due to their unusual and tunable material properties derived from spatial variations in compositions. However, achieving a comprehensive understanding of the mechanical and failure behavior of compositionally graded nanostructures, particularly at the atomic level, has remained elusive. In this study, molecular dynamics simulations are used to investigate the tensile mechanical and failure properties of CuNi nanowires with compositional gradients. The nanowires exhibit a dual variation in composition along the longitudinal direction following power-law functions. The findings demonstrate that Young's modulus, ultimate tensile strength, and yielding stress of nanowires decrease with an increase in the gradient index. Remarkably, the mechanical properties exhibit higher sensitivity to changes in the gradient index for nanowires displaying composition distribution in a convex function, while they exhibit lower sensitivity for those with concave functions. Furthermore, the necking and failure processes predominantly occur in regions with highly varied compositions. Moreover, as the gradient index increases, the distance between the necking position and the mid-plane of nanowires decreases. Additionally, this study provides a detailed discussion of the phase transitions that occur during the tension process.

Study of the tensile mechanical properties and failure mechanisms of CFRP screwed joints

Removable joint technology is commonly used in composite laminates for various load-bearing structures. However, existing research primarily focuses on bolted joints, there is relatively limited research on screwed joints in composite materials. This study investigates the influence of connected layer thickness and hole diameter on the tensile behavior of threaded joints in carbon fiber-reinforced polymer (CFRP) laminates. After fabricating different CFRP screwed joint specimens, tensile tests were conducted. The digital image correlation (DIC) technique captured the deformation process. The experiment results indicate a significant increase in load-bearing capacity with the increase in diameter. For instance, joints with an 8 mm diameter exhibited a load-bearing capacity of 10.82 kN. The increase in the connected layer thickness correspondingly enhanced the load-bearing capacity of the joint. The joint with a thickness of 7 mm had the highest load-bearing capacity of 8.83 kN. Besides, with the increase in the thickness of the connected layer, the failure mode transitioned from shear failure in the connected layer to screw pull-out. The tilt angle of the screw during the pull-out process also decreases with the increase in the connected layer thickness. Strain and out-of-plane displacement measurements under ultimate load conditions verify these observations.

Pyrolysis-recycling Utilization Properties Waste Wind Turbine Composite Blades

As a clean and environmentally friendly energy, wind energy is developing rapidly. With the development and construction of wind farms, wind turbines have reached their service life in succession and entered the stage of decommissioning. In this paper, the typical waste glass fiber reinforced epoxy resin composites wind turbine blades are studied and discussed, and the mechanical tensile properties and surface micro properties are analyzed. The tensile strength of blade materials pyrolysis residue was measured by universal testing machine, and the pyrolysis experimental residue of blade materials were characterized by SEM, the change law of micro morphology of blade samples in pyrolysis process were analyzed. The results show that when the pyrolysis temperature is 350.0 ℃, the loss rate of elastic modulus of pyrolysis residue of blade materials at this temperature is low, and the pyrolysis residue with good elastic modulus and tensile strength can be recovered.

The use of thermoplastic polyurethane composites to develop a model of the renal pelvicalyceal system by 3D printing

Composites based on thermoplastic polyurethanes (TPUR) were obtained using the twin-screw extrusion method. Influence of the addition of 6, 7 and 8 wt% silica and 1–3 wt%. aluminum oxide and 1–3 wt%. dibutyl phthalate (plasticizer) on Rockwell hardness, Charpy impact strength and tensile mechanical properties was tested. The best properties were obtained for a composite containing 8 wt% silica, 3 wt% aluminum oxide and 3 wt% dibutyl phthalates. For this composite, the renal pelvicalyceal system was obtained using the FFF method.

Random modeling of hemp fibers mechanical properties

The growing interest in vegetal fiber-based composite materials for reinforcing structural elements is prompting researchers to consider the inherent randomness, arising from various factors which are complex to model. For this reason a general probabilistic approach seems more appropriate to model all uncertainties regardless where they come from. In this paper, factory produced hemp ropes, and their components, are tested to obtain their tensile mechanical properties. In particular, 120 fibers with four different lengths, 55 yarns, 33 strands and 64 ropes are used to obtain a first statistical characterization of tensile strength, strain and Young modulus. These results are used to calibrate two commonly used random models such as Gaussian and three-parameters Weibull distributions and to give both qualitative and quantitative complete random characterization of the tensile properties of each hemp rope components. The obtained results are crucial to estimate vegetal fiber-based composite materials structural response.

Manufacturing process and annealing influence on the dynamic mechanical properties and physical structure of LLDPE thin films

Thin films of Linear Low-Density Polyethylene are used for stratospheric balloon applications. They undergo tensile mechanical stress on a wide range of temperatures [-95; 55]°C. The aim of this study is to compare the influence of blown film and double-bubble manufacturing processes on the crystalline phase and mechanical properties of the films through their operating temperatures (flight, storage, and transportation temperatures). Dynamic Mechanical Analysis and Differential Scanning Calorimetry have been used to monitor the dynamic mechanical properties in tension mode and the crystalline phase of the films respectively. The films mechanical properties are dependent on their manufacturing process. The double-bubble process allows isotropic tensile mechanical properties regarding stretching direction, whereas the blown film process favors only transversal direction. To simulate different storage conditions, annealing has been performed. The influence of annealing on the tensile mechanical properties of the films depends mainly on the internal stress stored during manufacturing. The double-bubble process produces a biaxially stretched film with a higher stretching ratio than blown films. The dissipated internal stress can be associated with thermal shrinkage and goes up to 10 % for the biaxially stretched film. The more internal stress is stored, the more E′ and E″ increases. Annealing also favors the formation of a secondary crystalline phase that is dependent on annealing temperature and time, and exhibits αc relaxation. After annealing, the amorphous phase is less stretched, and the crystalline phase keeps its orientation.

PA 10.10 and PA 6 composites with glass or basalt fibre: mechanical properties in dry and wet state

The effect of basalt and glass fibres and moisture on the impact strength, tensile mechanical properties and heat resistance of PA 10.10 and PA 6 was examined. It was shown that PA 10.10 composites can compete with PA 6 composites in terms of mechanical properties, in a humid environment. Their heat resistance was lower than that of PA 6 composites. Regardless of the type of polyamide, composites with glass fibre had better properties than those with basalt fibre.

Experimental investigation of physical and tensile mechanical properties of granite after different heating and cooling treatments

In this study a series of physical properties of granite were tested after different cooling treatments. Correspondingly, Brazilian splitting testing combined with acoustic emission (AE) testing was conducted on five groups of granite samples at different temperature levels, and scanning electron microscopy (SEM) was used to investigate the microstructure of granite. It was found that the P-wave velocity, hardness and thermal conductivity decreased with rising temperature. The tensile strength of granite was deteriorated by the action of temperature, and the progression of cracks was monitored using AE technology. The SEM results also indicated a significant increase in both the number and density of cracks in granite samples subjected to temperature variations compared to a naturally cooled group. In addition, after heating and cooling at different temperatures, samples with lower tensile strength exhibited rougher fracture surfaces, which were attributed to the generation of more thermal cracks during the heating and cooling processes. Moreover, a variation in the mechanisms for granite after temperature treatment is proposed.

Corn cob nanocellulose packaging for increasing the shelf life of food products

Studies were carried out to develop eco-friendly Packaging material for the extended shelf-life of food products. The current study sought to improve the coated bioactive film's hydrophobicity and antimicrobial properties by preparing active packaging based on biodegradable Poly Lactic Acid (PLA) containing 1 wt% Nanocellulose (NC) and various loadings of essential oil-prepared nanocomposites. Nanocellulose (NC) from Maize Cob was used as filler in the synthesis of nanopolymers enriched with Thyme oil, Cinnamon oil, clove oil, and Rosemary oil. Characterization of nanopolymer-coated bags and their effect on enhancing the shelf-life of food products in different temperature conditions was also studied. The fabricated nanocomposite and nanocellulose were characterized using FTIR, SEM, XRD, Contact angle, TGA, and Tensile mechanical properties. The fabricated nanocomposite-coated paper cum bag shows good hydrophobic properties as well as antimicrobial and insecticidal properties. The results showed that adding essential oils and dispersing nanocellulose to the PLA matrix strengthened its mechanical qualities as well as its efficacy for biodegradation and antimicrobial properties. The current work provides extremely promising materials for future applications in food packaging applications using sustainable nanocomposite-based biodegradable and antimicrobial coated paper cum bags.

Effect of the molar mass of polyimide based on pyromellitic dianhydride and 4,4′‐oxydianiline on dielectric and mechanical properties of nonwoven oriented polyimide materials

AbstractThis work is dedicated to the development and investigation of the properties of low‐dielectric‐constant nonwoven materials obtained by electrospinning from a polyimide‐based polymer, PMDA‐ODA, which is composed of pyromellitic dianhydride (PMDA) and 4,4′‐oxydianiline (ODA). The influence of the molar mass of PMDA‐ODA on the structural, mechanical, and dielectric properties of the resulting samples has been investigated. The molar mass of the polyimide has been determined through light scattering and viscosity measurements of polyamic acid solutions. As the molar mass of PMDA‐ODA increases from 13.400 to 49.300 g/mol, the glass transition temperature of the produced nonwoven samples increases, and their tensile mechanical properties are improved. The dielectric constant of PMDA‐ODA nonwoven polyimide materials varies from 1.55 to 1.91 at a temperature of 30°C in a frequency range from 1 Hz to 1 MHz, depending on the molar mass of the polymer used.

Effects of Ti content on the tensile ductility, lattice distortion and mechanical properties of VNbTaTix refractory high-entropy alloys

Refractory high-entropy alloys (RHEAs) have remarkable properties like high strength and thermal stability at high temperatures. Their practical application is hindered by ambient brittleness and inferior formability. Titanium (Ti) is recognized as a crucial element in improving the ductility and oxidation resistance of RHEAs, but its plasticizing mechanism is still unclear. To address this, a series of body-centered cubic (BCC) single-phase VNbTaTix alloys were designed. The alloys exhibited exceptional ductility and cold-rolling formability at room temperature. Remarkably, the tensile fracture elongation of VNbTaTi alloy was about 26.9%, which surpassed most RHEAs. The major plastic mechanisms of the alloys are a/2<1 1 1>-type dislocation and {1 1 2}<1 1 1>-type twinning. Solid solution strengthening was identified as the primary strengthening mechanism. Although Ti reduced the solid solution strengthening effect, it contributed to weight reduction and enhanced local lattice distortion. This study not only designed several RHEAs with ductility but also provided insights into the effect of Ti content on their phase stability, lattice distortion, and strength mechanisms. These findings have significant implications for designing new RHEAs with ambient ductility.

Development and characterization study of bagasse with stubble reinforced polyester hybrid composite

In the present day, recycling and reducing environmental pollution are the primary objectives of sustainable development. A lot of experts are considering the possibility of creating a new composite technology with waste materials. This work aims to investigate the effects of waste material on mechanical and hydrophobic properties, with a particular focus on bagasse fiber with stubble. The tensile, flexural, impact, and hardness properties of bagasse with stubble polyester composite were investigated to see if it may be used as a novel material in various engineering applications for a longer life. To improve the impact resistance of the composite, bagasse fibers is mixed in different ratios with polyester and stubble as infill. Additionally, a very tiny amount of TiO2 was added to every sample. Tensile, flexural, and impact mechanical properties were assessed using the Universal Testing Machine, the Rockwell Hardness Testing Machine, and the Izod Impact Test. Samples were hand-set out using varying weight ratios of binder, filler, and fiber. The study's findings demonstrated that the sample with a higher percentage of bagasse fiber demonstrated better mechanical and hydrophobic qualities as compared to the neat and other samples. It is an economical, long-lasting, and environmentally responsible option for a variety of applications.

Dynamic tensile mechanical properties of red sandstone under different pulse widths and amplitudes: Brazilian disk experiment and macroscopic and microscopic analysis

To investigate the dynamic tensile mechanical properties of red sandstone under varying impact pulse widths and amplitudes, we employed the response surface methodology to examine the dynamic response characteristics of sandstone under different bullet lengths and impact velocities. Subsequently, a dynamic damage constitutive model for sandstone was developed. Macroscopic and microscopic features of sandstone were analyzed through digital image correlation (DIC) and scanning electron microscopy (SEM) experiments. Additionally, ANSYS software was utilized to analyze stress wave characteristics under controlled shock waves and the impact of geological factors on rock fracturing effects. The findings revealed the following. First, the length and impact velocity of bullets exhibit an interactive effect on the tensile response characteristics of sandstone. Peak load, energy consumption rate, and energy density display a positive correlation with bullet velocity. Second, according to the DIC results, the fractal dimension of the crack is negatively correlated with the length of the bullet during equal energy impacts. Third, microscopic failure modes included fractures along particle cementation and through particles, with section roughness decreasing as bullet length increased under equivalent energy impacts. Fourth, a dynamic damage constitutive model (R2≥0.84) was established based on the Zhu-Wang-Tang (Z-W-T) model and Drucker-Prager (D-P) criterion, clarifying model parameters and influence rules. Fifth, under controlled shock waves, the pulse width facilitates crack propagation, while the pulse amplitude initiates crack formation. Optimal rock breaking efficiency is achieved when stress waves exhibit a large pulse width and low radiation values, meeting specific threshold conditions.