Mechanical Design Properties Research Articles

Reveal of relationship between microscopy architecture and mechanical performance of Y/Bi substituted Bi-2212 engineering ceramics.

This study aims to find out how the crystallinity quality, surface morphology, and mechanical performances change with the substitution of yttrium (Y) for bismuth (Bi) impurity within molar ratios of 0.00 ≤ x ≤ 0.12 in the Bi2.0-xYxSr2.0Ca1.1Cu2.0Oy (Bi-2212) cuprates to reveal the dependence of micro surface topology on the substitution mechanism and achieve a strong relation between the impurity ions and crystallization mechanism. The materials are prepared by ceramic method. It is found that all the experimental findings improve remarkably with increasing yttrium impurity molar ratio of x = 0.01. Scanning electron microscopy (SEM) images indicate that the optimum Y ions strengthen the formation of flaky adjacent stacked layers due to the changes of thermal expansion, vibration amplitude of atoms, heat capacitance, reaction kinetics, activation energy, nucleation temperature, thermodynamic stability, and intermolecular forces. Besides, new engineering novel compound produced by optimum Y ions presents the best crystallinity quality, uniform surface view, greatest coupling interaction between grains, largest particle size distributions/orientations, and densest/smoothest surface morphology. Hardness measurement results totally support the surface morphology view. Moreover, mechanical design properties and durability of the tetragonal phase improve significantly with increasing replacement level of x = 0.01 due to the induction of new surface residual compressive stress areas, slip systems, and chemical bonding between the foreign and host atoms. Besides, the same sample exhibits the maximum strength and minimum sensitivity to loads depending on reduction of stored internal strain energy and degree of granularity. Consequently, cracks tend to propagate predominantly within the transcrystalline regions. Furthermore, each material investigated exhibits the characteristic behavior of the indentation size effect. In summary, the optimum Y-doped Bi-2212 sample paves the way for the expanded use of engineering ceramics across various applications based on the enhanced service life. RESEARCH HIGHLIGHTS: The presence of the optimum yttrium impurity significantly decreases the Ea value. As the Y/Bi replacement increases up to the molar substitution level of x = 0.01, the mechanical design properties and durability of the tetragonal phase enhance significantly.

Evaluation of key mechanical design properties and mechanical characteristic features of advanced Bi-2212 ceramic materials with homovalent Bi/Ga partial replacement: Combination of experimental and theoretical approaches

This study models the variations in the key mechanical design properties and mechanical characteristic features of Ga substituted Bi-site Bi-2212 ceramics prepared within the different molar ratios of x = 0.000, 0.005, 0.010, 0.030, 0.050, 0.100 and 0.300 with the assistant of available theoretical approaches; namely, Meyer’s law, proportional sample resistance, elastic/plastic deformation, modified proportional sample resistance model, Hays Kendall and indentation-induced cracking methods for the first time. The mechanical modeling parameters are gathered from the microhardness (Vickers) experimental tests performed at various applied loads interval 0.245 N–2.940 N. The results provide that the key mechanical design features improve systematically with the augmentation of trivalent Bi/Ga partial replacement level up to x = 0.05 due to the rapid decrement in the main structural problems; namely, the grain orientations, lattice strains, distortions, dislocations, grain boundary interaction/coupling problems, crack-initiating and crack-producing omnipresent flaws in the advanced Bi-2212 ceramic system. Accordingly, the optimum Ga inclusions strengthens the mechanical durability towards the applied stress due to the increased stabilization in the durable tetragonal phase. After the critical substitution amount of x = 0.05, the mechanism turns reversely, and the general mechanical characteristic features including the stiffness, mechanical durability and strength degrade remarkably. Additionally, the mechanical modeling results demonstrate that the Bi/Ga impurity leads to vary positively the quality of standard indentation size effect (ISE) feature until x = 0.05, beyond which the excess Ga additives damage seriously ISE feature of Bi-2212 inorganic compounds. Besides, the indentation-induced cracking (IIC) model is noticed as the best method to describe the true microhardness parameters of Bi/Ga substituted Bi-2212 compounds for the mechanical characterization.

Young's Modulus and Poisson's Ratio Estimation Based on PSO Constriction Factor Method Parameters Evaluation

The knowledge of materials' mechanical properties in design during product development phases is necessary to identify components and assembly problems. These are problems such as mechanical stresses and deformations which normally cause plastic deformation, early fatigue or even fracture. This article is aimed to use particle swarm optimization (PSO) and finite element inverse analysis to determine Young's Modulus and Poisson's ratio from a cantilever beam, manufactured in ASTM A36 steel, subjected to a load of 19.6 N applied to its free end. The cantilever beam was modeled and simulated using a commercial FEA software. Constriction Factor Method (PSO variation) was used and its parameters were analyzed in order to improve errors. PSO results indicated Young's Modulus and Poisson's ratio errors of around 1.9% and 0.4%, respectively, when compared to the original material properties. Improvement in the data convergence and a reduction in the number of PSO iterations was observed. This shows the potentiality of using PSO along with Finite Element Inverse Analysis for mechanical properties evaluation.

Time and temperature effects on the mechanical properties of glass-filled amide-based thermoplastics

Time-dependent mechanical design properties of four commercial thermoplastic resin systems were investigated at temperatures of 23, 100, and 150°C. The test materials were glass-filled polyamides and polyphthalamides. Experiments were performed to characterize creep, creep-rupture and tensile behaviors after isothermal aging. Creep-rupture data were used to create master curves using a Sherby–Dorn analysis. Although each material possessed a different property advantage, a polyphthalamide with 33% glass reinforcement exhibited a good combination of creep resistance, strength and ductility. The reported results provide information that is critical for the design and development of structural thermoplastic components.

Determination of Mechanical Design Properties of Materials

Abstract The design of most structural and mechanical parts is based on the modulus of elasticity and a permissible stress level for the materials. Traditionally, these properties are determined from the information obtained by means of tension tests. An alternate method of determining the necessary design parameters has been developed. It is based on the dynamic determination of the elastic energy at maximum amplitude and the energy dissipation per cycle of a test sample. The method is particularly useful for bending or torsional tests. It allows the accurate determination of the elastic moduli of materials and determines stress values which cause a permanent strain smaller or equal to a predetermined value. Several materials have been tested in bending in this manner. The elastic moduli and stresses causing permanent strains smaller than a specified amount have been measured. The results have been compared with those obtained by means of tension tests. Excellent agreement has been obtained.