Papers by Keyword: Elastic Properties

Abstract: The structural, electronic and elastic properties of nonmagnetic LuPd₃ compound, which crystallize in AuCu₃-type structure, are studied using first principles density functional theory based on full potential linearized augmented plane wave (FP-LAPW) method. The calculations are carried out within the PBE-sol GGA for the exchange correlation potential. The ground states properties such as lattice parameter (a_o), bulk modulus (B) and pressure derivative (B') have been obtained using optimization method. The elastic properties such as Young’s modulus (E), Poisson’s ratio (σ) and anisotropic ratio (A) and thermal are predicted for first time. The ductility of these compounds has been analyzed using Pugh criteria.

Abstract: According to the structural features of 3-D braided composites, the whole structure is divided into three types of sub-unit cells, these are the interior unit cell, the surface unit cell and the corner unit cell. Considering the bending of fiber bundle and the deformation of cross-section which are caused by the space fiber extrusion and twist together, the corresponding geometric analysis models for every type of sub-unit cell are established, and the engineering elastic constants of the 3-D braided composites are predicted. The results show that the calculated results well agree with the experimental results, and the effectiveness of the model is verified.

Abstract: Properties of an interpenetrating metal–ceramic composite with freeze-cast preforms are investigated. For the estimation of elastic properties of the composite numerical homogenization approaches for 2D and 3D finite element models are implemented. The FE models are created based on micro-computed tomography (μCT) images. The results of the numerical 2D and 3D modeling coincide and are in good agreement with available experimental measurements of elastic properties.

Abstract: The dynamic performance of suspensions plays direct role in vibration control of railway vehicles and also has great impact on the ride comfort and operation stability. For assessment of the influence, a method of sensitivity analysis was performed, in which a Multi-Body System (MBS) dynamic model for the HXN5 locomotive counting for significant DOFs and nonlinearities was developed in SIMPACK platform and validated by real tests. More than tens of dynamic simulations were performed by a variety of damping and stiffness coefficients of the primary and secondary suspensions. By simulation, it is found that the vertical stiffness and damping of the primary suspension have the most sensitive influence. The lateral stiffness of the primary suspension, the longitudinal and lateral stiffness as well as the longitudinal and vertical damper of the secondary suspension possess the least effect on the railway locomotive vibration characteristics. It is also shown parameters of the longitudinal stiffness of the primary suspension, the vertical stiffness and lateral damper of secondary suspensions are of intermediate influence.

Abstract: Outlast fiber is a kind of thermostat fiber that could absorb and release heat according to the changed environment temperature. It has been widely used in thermostat textiles. The outlast/viscose blended yarn we researched in this paper will be used in apparel fabric. As the demand in durability and comfort property of apparel fabric, we characterized the yarn by regain, tensile and damage properties, elastic property, differential scanning calorimetry (DSC) and thermo gravimetric analysis (TGA). The experiment results show that the outlast/viscose blended yarns have good hydroscopicity, elastic property, temperature adjusting performance and thermal stability.

Abstract: The elastic properties of a Ti₃Al intermetallic compound were studied using full potential (FP LAPW ) with the APW+lo method. The FP-LAPW is among the most accurate band structure calculations currently available and is based on the density functional theory with general gradient approximation for the exchange and correlation potential. This method provides the structural properties of the ground state as bulk modulus, equilibrium lattice parameter, and equilibrium minimum energy, and the elastic properties as shear modulus, young modulus, Zener coefficient (anisotropy), and Poisson coefficient. The calculated elastic properties are coherent with the elastic properties of the material.

Abstract: The stuctural, elastic and thermodynamic properties of B2-NiAl and L1₂-Ni₃Al intermetallic compounds are systemically investigated. Using a first principle pseudopotential plane-wave method, several basic mechanical parameters of B2-NiAl and L1₂-Ni₃Al crystals, such as the equilibrium volume, the bulk modulus, the elastic constants, the Zener anisotropy factor, the Poisson’s ratio, the Young’s modulus and isotropic shear modulus are firstly calculated. And then the temperature dependence of the equilibrium volume, the bulk modulus, the thermal expansion coefficient, the heat capacity, the Debye temperature and the Grüneisen parameter are further evaluated in the framework of a quasi-harmonic Debye model. Finally, a special attention is paied on the mutual influence of pressure and temperature on mechenical and thermodynanic properties of B2-NiAl and L1₂-Ni₃Al intermetallic compounds in the range of 0-20 GPa and 0-1000 K.