Papers by Keyword: Elastic Modulus

Abstract: β Ti-18Mo-xCr alloy has been widely used as an orthopedic implant material because this alloy has the advantage of high strength a lower modulus of elasticity than commercial alloys Ti-6Al-4V, good corrosion resistance. and formability. This research aims to find alloys with high corrosion resistance and low modulus of elasticity and identify the presence of phase β after heat treatment. Ti-18Mo-7Cr is obtained from the melting process using an arc melting furnace followed by heat treatment (solution and aging treatment). To determine the modulus of elasticity using a sonelastic tool and hardness test using Microhardness Vickers. The EIS method was used to determine the corrosion resistance using a 0.9% NaCl solution as a simulated body fluid. The modulus of elasticity owned by the solution treatment alloy tends to be lower than that of the aging alloy. The lowest elastic modulus value and the highest hardness value are found in the Ti-18Mo-7Cr ST850 alloy, which is 91 GPa and 471.42 HV. For corrosion resistance, the aging treatment alloy shows a lower corrosion rate than the solution treatment alloy and is much lower than that of the Ti-6Al-4V alloy. On the other hand, the solution treatment can stabilize the β phase and reduce the corrosion rate due to heating below transus temperature, but aging with a longer holding time can also reduce corrosion resistance more than the corrosion resistance of the solution treatment. The alloy Ti-18Mo-7Cr AT500 has the lowest corrosion rate among the samples in this study, which is 0,0004225 mmpy.

Abstract: The first polycaprolactone material experimental and clinical studies were published in 1960-1970, which proved its biocompatibility and determined the absence of toxic properties. At the same time it did not receive widespread use due to insufficient rigidity and strength compared to metal implants. For a long time, relatively solid materials were used to treat injuries to the musculoskeletal system segments. The progress in materials science, development of new sterilization methods has again changed the attitude towards biomaterial implants and has attracted the attention of clinicians. In this regard, the development of predictive modeling methods to determine effective mechanical properties and optimal geometric structure of porous biomedical materials is an important task. Modeling the internal architecture of porous materials and their properties by the finite element method using computed tomography data is as close as possible to the real picture, but it is quite laborious to apply directly to large-sized scaffolds. Properties of such materials largely depend on the technology of their manufacture and processing, the geometric dimensions and cell shape. In this regard, the development and improvement of analytical methods for assessing properties of cellular structures remains relevant. The aim of this study is determining polycaprolactone effective elastic modulus based on modified Gibson-Ashby open-cell model as an implant material and osteochondral defects treatment. A practical analytical method for estimating the elastic modulus of a cellular material regardless of the scaffold volume and shape is proposed. Calculations are performed for polycaprolactone produced using selective laser sintering technology. A comparative analysis of the obtained results with experimental studies of other authors is carried out. The results can be used for evaluation analysis and calculations of medical devices strength and stiffness made of porous polycaprolactone for the bone defects treatment.

Abstract: The aim of this study was to investigate the feasibility of manufacturing typha-based materials with a lime-based binder. For this purpose, three types of lime with different compositions were tested to produce lime-based typha concretes. The mechanical performance (compressive strength and apparent modulus of elasticity) of the materials developed was evaluated as a function of binder content and binder type. Two types of formulations were studied: one with a binder/aggregate ratio of 3, called F3, and the other with a binder/aggregate ratio of 2, called F2. Water absorption kinetics and typha particle size analysis were also studied. The dry density, compressive strength and apparent modulus of elasticity of typha concretes were determined. The results showed a reduction of mechanical performance as the binder/aggregate ratio decreased. The density of typha concretes range from 520 kg/m3to 396 kg/m3. The best mechanical performances were obtained with Thermo Tradical and Earasy binders. When the binder/aggregate ratio was reduced from 3 to 2, stress at 10% strain ranged from 0.6 MPa to 012 MPa and apparent modulus of elasticity from 31.5 MPa to 3.57 MPa. This study showed that binder composition has a significant impact on the mechanical performance of plant-based concretes.

Abstract: The paper presents a study of the behavior of particles of different sizes in a medium, focusing on their settling rate, hardness and elastic modulus. The settling rate was calculated using Stokes’ law, which shows a quadratic dependence on the particle radius. The results demonstrate that particles with a diameter of 100 μm settle significantly faster compared to smaller particles (1 μm and 10 μm), while the latter remain suspended for a long time due to the significant influence of viscosity. Mechanical properties of particles, such as hardness and elastic modulus, exhibit size dependence: hardness decreases with decreasing particle size, making smaller particles more vulnerable to mechanical stress. The elastic modulus shows a weak decrease for small particles, which may affect their resistance to deformation during collisions. The results obtained are important for the practical use of particles in various technological processes, such as liquid purification, development of nanomaterials, transport of solid particles in liquid or gas flows. The study emphasizes the need to consider the relationships between the physical, mechanical and dynamic characteristics of particles for optimizing technological processes and developing new materials.

Abstract: The mechanical properties of anodic oxide films of Nb, Ta and Zr were studied by the nanoindentation method. Anomalously high elastic recovery after deformation was observed for oxides with thickness of 20 nm. An analogue of this behavior can be elastic membrane fixed on soft base that does not prevent the membrane from bending. Increase of the oxide thickness to 300 nm reduced the effect associated with the high elasticity of oxide and easy deformation of the soft metal substrate, and was accompanied by an increase in the plastic component of deformation, which is similar to the behavior of ceramic materials with low elastic and significant residual plastic deformation.

Abstract: Bamboo can be used for a variety of purposes, whether using the bamboo culm in structures works or using bamboo bundle or bamboo fibers as a reinforcement in composite materials. However, the critical item that should be considered when using bamboo materials is the humidity condition of the environment. The influence of humidity on the mechanical properties of bamboo materials can potentially lead to damage or degradation. The objective of this research is to investigate the influence of relative humidity (RH) on elastic modulus of bamboo bundle. In this research, 3 years old Dendrocalamus bamboo stem at 3-6 m in height without node was used to prepare the bundle samples. The bamboo stem was dried in the oven at 105 °C then hand pulled and cut to get the bamboo bundle with 30 mm in gage length and 0.06-0.09 mm² in cross-section areas. The elastic modulus of bamboo bundles was determined according to ASTM D3379 standard under 8 different relative humidity; 30%, 35%, 50%, 55%, 70%, 75%, 80%, and 85% RH, whereas paper grips technique was applied to prevent damage from the machine clamps. The results indicated that the relative humidity does not affect the value of the loaded or unloaded elastic modulus of bamboo fiber bundle. For the low value of relative humidity, here 35%-55%, the value of elastic modulus of bamboo bundle is quasi-stable with the RH with the average value 25.93 GPa while the elastic modulus was gradually decreased for the high value of RH (>70%) with the minimum value of 24.43 GPa at 85% RH. Implying at high humidity condition, the humidity or the amount of water vapor in the air affects to the bamboo bundle be softened or more flexible, which helps the process of bending or forming bamboo bundles easier.

Abstract: In general, composite materials are widely used in many industries. A composite material is a material composed of two or more components. Such a composite material differs in its properties from the individual components of the entire composite. This contribution is aimed at evaluating the parameters of selected composite materials - wood fiber boards, carbon prepreg boards and epoxy boards. The measured quantities that were investigated on the given materials were the modulus of elasticity, the loss modulus and the tan delta angle. To evaluate the properties of the given composite materials, a dynamic-mechanical analysis using the DMA Q800 device from TA Instruments was used. Three samples were measured from each material. From the measured values, it is demonstrable for the modulus of elasticity that the greatest mechanical disturbance began to occur gradually due to the influence of temperature and frequency with three materials in this order: fiber board - carbon prepreg board - epoxy board. From the obtained values ​​of the loss modulus, it was proven that the sample - wood fiber board - had the lowest glass transition temperature. Finally, regarding the measured values ​​of the glass transition temperature for the loss angle (tan delta), it can be said that the wood fiber board also has the lowest damping ability.

Abstract: Pineapple leaf is a significant agricultural waste in pineapple processing plants. The leaf comprises several carbohydrate polymers, including cellulose, hemicellulose and lignin. This research investigated the use of microcrystalline cellulose (MCC) extracted from pineapple leaves as a reinforcing agent in polycaprolactone (PCL) biopolymer at various MCC concentrations. MCC was extracted from pineapple leaves through several processes, including alkali treatment with sodium hydroxide (NaOH), bleaching with sodium hypochlorite (NaOCl), and acid hydrolysis with oxalic acid. Fourier transform infrared (FTIR) spectroscopy confirmed the presence of cellulose from the extracted MCC, and field emission scanning electron microscopy (FESEM) analysis revealed that the particles are of micro-size. The tensile testing results show that the elastic modulus of PCL-based biocomposite increases with higher MCC concentrations. The stiffness of the biocomposites increased by up to 9.5% with the addition of 2 wt.% of MCC as a reinforcing filler, indicating that MCC effectively enhances the mechanical properties of the biocomposite.

Abstract: In this study, the elastic modulus of the 3D-printed Nylon filament reinforced with chopped carbon fiber as the matrix material and fiberglass (FG) as the reinforcement material, was evaluated using the Rule of Mixtures. Different configurations with various numbers of FG layers were added to the specimen, and all were subjected to tensile tests. The elastic modulus from the calculated values using ROM (Ε_c) and experimental results from the actual tensile test (E) of the 3D-printed composite material were compared. The results showed that the discrepancy between the Ε and Ε_c increases as the number of reinforcement layers also increases.

Abstract: The use of silica sand tailings without leaching as a reinforcement in the development of composites remains a material class known for outstanding properties. However, owing to the availability, least expensive, and physical properties of silica beach sand, this study investigates the effect of non-leached silica (SiO₂) beach sand particulates on the mechanical and tribological characteristics of aluminium (Al) alloy matrix composites. In the study, an AA6061 alloy matrix was reinforced with varying content of SiO₂ beach sand (0, 20, 30, and 40 wt%) using the stir casting process. The SEM results revealed uniform dispersion of the beach sand particulates in the resultant composites with minimal agglomerations up to 30 wt% loading. Thus, the hardness and elastic modulus of the SiO₂/AA6061 alloy composites were improved by 326.7% and 90.9%, respectively, at 30 wt% SiO₂ particle addition. In addition, with the introduction of the SiO₂ particles in the alloy matrix, a reduction in the coefficient of friction by 24.5% and wear rate by 40.79% was recorded compared to the pure Al alloy. These findings indicate the substantial potentiality of silica beach sand particulates reinforced Al alloy matrix composite material as a promising candidate for mechanical load bearing, frictional components, and high-performance engineering applications including construction, automotive component, airframe, marine and rail transport.