Papers by Keyword: Young’s Modulus

Abstract: In recent years, high-entropy alloys (HEAs) have attracted significant attention owing to their remarkable physical properties such as high strength. It has also been reported that HEAs have a high potential as biomaterials. Bcc-type bio-HEAs possess high strength and biocompatibility equivalent to those of pure titanium. Bio-metallic materials require a low Young's modulus, similar to that of natural bone, but the Young's modulus of bio-high entropy alloys has not yet been clarified. Therefore, this study elucidates the relationship between microstructure control and Young's modulus in titanium-based bio-HEAs. The TiNbTaZrMo-based bio-HEAs were composed of two bcc phases. These two phases correspond to dendrite and interdendrite structures, respectively. In this study, it was found that by varying the volume fractions of these two phases, it is possible to control the Young's modulus.

Abstract: This study investigates the mechanical degradation of nylon 6,6 under tensile stress, induced by accelerated aging via ultraviolet (UV) radiation [1-3]. Specimens were fabricated and exposed to controlled UV doses, simulating outdoor weathering conditions. Tensile properties were evaluated, revealing a significant reduction in tensile strength and elongation at break with increasing UV dose. The predominant degradation mechanism was photo-oxidation, evidenced by polymer chain scission and the formation of functional groups altering the material's molecular structure[4,5]. Specimen surfaces exhibited cracks and fissures, contributing to mechanical strength loss. These findings are critical for nylon 6,6 applications in telecommunications and energy industries, where UV exposure is unavoidable. Understanding this degradation is essential for optimizing the durability and reliability of critical infrastructure. This study lays the foundation for developing advanced protective materials and coatings, enhancing the safety and efficiency of outdoor systems.

Abstract: This study focuses on the numerical estimation of the effective Young's modulus of single-walled carbon nanotubes (SWCNT) using a continuum mechanics approach tailored for additive manufacturing applications in prosthetic limbs. In our finite element model, the positions of carbon atoms within the SWCNT are represented as nodes linked by beam elements that embody the geometrical and elastic mechanical properties derived from interatomic forces. These forces are quantitatively assessed by equating them to the total interatomic potential energies of the SWCNT's molecular structure. Employing an equivalent continuum technique, we evaluate the effective elastic properties across various SWCNT configurations and benchmark our findings against existing numerical and experimental data from the literature. Our results, which align closely with published studies, demonstrate the isotropic behaviour of SWCNT and reveal a significant dependence of stiffness on the modelled wall thickness. These insights are critical for the development of enhanced prosthetic limbs through additive manufacturing, where material properties such as stiffness and durability are paramount.

Abstract: The existing discrepancy between theoretical models and experimental results in describing the elastic properties of ultra-thin nanofilms (less than 10 nm) is primarily attributed to the oversight of the surface layer thickness impact. To address this, a new model incorporating a surface layer with thickness is proposed in this article. Utilizing a layered model, the Young’s modulus of nanofilms approaches that of bulk materials as the film thickness becomes infinitely large, equating to the Young’s modulus of the bulk material in both layered and unlayered models. The dimensional unit of the surface elastic coefficient in the layered model differs from that of the unlayered model, approximately by the thickness of the film. Numerically, the former is more than double the latter. Predictions using the layered model for ultra-thin films comprising only two surface layers reveal a hardening effect in materials such as Si, Ge, InAs, and GaAs. The increase in Young’s modulus for these materials is 20.81%, 95.28%, 79.03%, and 84.04%, respectively, compared to their bulk counterparts. Moreover, a continuous increase in the Young’s modulus is observed as the thickness further decreases.

Abstract: Atomic Force Microscopy (AFM) technology has ushered researchers to directly observe surface topology and the substrate mechanical properties using specialized probe. AFM is one of the microscopic techniques with the highest lateral resolution which can be employed in air or even in liquids. In this experiment, we characterized the local elastic properties of the polyacrylamide (PA) hydrogel using Atomic Force Microscopy (AFM). PA consists of huge units of an organic acrylamide monomers which can be saturated to form a highly water-swollen hydrogel. The hydrogel offers tunable density with a high degree of pliability which depends of its applications. Such applications of PA hydrogel can be in cell substrate studies and measurement of cell-generated forces. Our results with AFM measurement yielded force-distance curves were used to determine the elastic behaviour of the polyacrylamide (PA) hydrogel. Analysis has shown that 15% w/v PA hydrogel concentration has Young’s modulus, Y_av=1608.9 ± 1.3 kPa (n=8) and transverse stiffness, K_av=88.7 ± 9.7 μN/nm (n=8) at Thus, elasticity measurements has provided useful insights for the future experiment on traction force microscopy with amoeboid organism.

Abstract: Piezoelectric ceramics possess very high piezoelectric coefficients but lacks the conformability for using them in flexible devices, in high-resolution sensing devices that can be integrated to human skin and other such applications. This problem can be resolved by blending them in appropriate proportion with polymers which are intrinsically light weight, stable and flexible. In this paper polymer composites xPZT– (1-x) PVDF (x= 0, 0.025, 0.05, 0.10, 0.15, 0.20 and 0.25) were prepared by solution casting method and their dielectric and its mechanical properties were studied. Given that PZT has a very high dielectric value, the composite's dielectric constant grew as the filler concentration increased which shows better dipole alignment in the composite. With an increase in filler concentration, the composite loses flexibility and tensile strength. Due to their greater Young's modulus than pure PVDF film, the films with compositions x=0.025 and x=0.05 could have better piezoelectric characteristics.

Abstract: The usage of reinforcing fibers extracted from nature is increasing in the present decade due to increasing the demand for biodegradability and environmentally friendly materials. In this paper, biodegradable sisal fiber and corn starch powder mixed thermoset and thermoplastic composite are prepared and tested for Young’s modulus. The effect of sisal fiber weight fraction on the Young’s modulus is identified at constant content of corn starch powder. Later, using Micromechanics approach and Finite Element Method simulation studies are performed to estimate transverse Modulus, Shear modulus, major and minor Poisson’s ratio of the sisal and starch based polymer composites. It is found that the composites prepared with sisal fiber and corn starch powder are a promising replacement for plastic reinforced composite to promote the biodegradability, especially under high weight fraction of sisal fiber

Abstract: The results of the experimental study of the mechanical properties and structure of the Co-9.5Al-2.9Mo-4Nb, Co-9.1Al-5.2Mo-4.7Nb, and Co-8.9Al-6.5Mo-9.3Nb alloys were presented. The Young’s moduli in the studied alloy samples were found to be smaller than those of Ni₃Al-based and Co₃(Al,W)-based alloys. The eutectic structure was observed in all studied alloys. Cuboids of the Co₃(Al,Nb,Mo) intermetallic compound with L1₂ crystal structure were found by TEM study.

Abstract: The aim of this study was to determine the compressive mechanical properties and the energy absorption characteristics of a bio-composite material based on lime, wheat straw, and additives (protein and entraining agent). The selected samples with fiber to binder ratio of 30% were subjected to compression tests at different strain rates (1 mm/min, 10 mm/min, and 100 mm/min), in the perpendicular and parallel directions to fiber orientation. Image analysis supported with Digital Image Correlation (DIC) method is performed to follow longitudinal and lateral deformations, thus making it possible to evaluate elastic properties. The results show that the highest density and compressive strength in the parallel direction are ~349 kg/m³ and ~0.101 MPa, respectively. The perpendicular specimens at 100 mm/min of speed test showed the highest values of densification strain, stress plateau, energy efficiency, and absorbed-energy of 47.27%, 0.32 MPa, 16.98 %, and 13.84 kJ/m², respectively. The values of Young’s modulus identified with DIC are significantly different from those determined by the slope of the linear part of the stress-strain curve. A slight influence of strain rate on mechanical properties is observed.

Abstract: Four different plastic deformation modes of pure molybdenum in powder metallurgy were studied, including single tensile, single torsion, tensile-torsion and compressive-torsion. Then the influence of these four plastic deformation modes on the micro-mechanical properties of pure molybdenum in powder metallurgy was studied by the micro-indentation method. The results show that the accumulated strain before deformation instability or fracture of the studied material caused by different plastic deformation modes is different, while showing a regular variation. And the mean indentation hardness along the radial direction of the sample also change regularly, which results in different strengthening effects on the molybdenum material itself. The damage inside the deformed material will cause the apparent modulus of elasticity measured by micro-indentation to decrease significantly.