International Journal of Computational Materials Science and Engineering

Quenching is commonly used for improving material properties of steel tubes because of their numerous applications. However, quenching generates some residual stress and deformation in the material due to rapid temperature fluctuations. The properties of the steel are strong functions of these variable temperatures and therefore, the estimated stress and deformation by constant property or static quenching analysis are not very realistic. This study describes the first extensive study of the quenching process of a steel tube including temperature dependent properties by three liquid quenchants using the dynamic fluid–structure interaction quench model. The cooling characteristics of the three liquid quenchants are compared to each other along with the transient temperature distributions in the steel tube. The time-varying nodal, axial, and radial residual stress and deformation of the tube are studied. It is found that, the effectiveness of quenching does not depend only on a particular quenchant, but also on the temperature-varying properties of the steel and the uniformity of the cooling which ultimately determine the criteria for selecting a suitable quenchant for a specific purpose.

The effect of local thermal nonequilibrium on the steady state heat conduction in metal foam tube heat exchanger as a porous layer in the presence of internal heat generated by considering the thermal conductivity coefficient as a function of temperature was investigated. A two temperature model is investigated by using reconstruction of variational iteration method (RVIM). The obtained results from RVIM are compared with the numerical results of Maple. These comparisons reveal that RVIM is a very powerful and precise approach to solve nonlinear ordinary differential equations and there is a good agreement between them. In this study, the effects of porosity and internal heat generation on the temperature distribution in the solid and liquid phases are presented.

The second order statistics of transverse nonlinear central deflection of elastically supported piezoelectric laminated composite sandwich plate (ESPLCSP) subjected to hygro-thermo-mechanical loading using micromechanical approach is evaluated in this paper. System randomness as micro-level material properties of fiber and matrix, material properties of piezoelectric, laminate thickness, lamination angle, foundation parameters, and load intensity are taken as independent random variables. The mechanical loading is taken as uniformly distributed and sinusoidal loadings. The secant function based shear deformation theory (SFSDT) with von-Karman nonlinearity is used for basic formulation. The elastic and hygrothermal properties of the composite material are considered to be dependent on temperature and moisture concentration have been evaluated utilized micromechanical modeling. A Newton–Raphson method based on $C^0$ nonlinear finite element method combined with mean centered second order perturbation technique (SOPT) proposed by present authors for the composite plate is extended for sandwich composite plate. The effect of random system properties with changing the plate geometry, stacking sequences, support conditions, foundation parameters, piezoelectric layers, fiber volume fraction and temperature, and moisture distribution on ESPLCSP is presented. The performance of proposed approach is validated through comparison with those available in the literature and independent Monte Carlo simulation (MCS).

In this paper, we employ the big data method to structural analysis by considering the correlations between loads and loads, loads and results and results and results. By means of fundamental mathematics and physical rules, the principle, feasibility and error control of the method are discussed. We then establish the analysis process and procedures. The method is validated by two examples. The results show that the fast simulation method based on big data is fast and precise when it is applied to structural analysis.

Using the interpolating moving least-squares (IMLS) method to form the shape function, a novel improved element-free Galerkin (IEFG) method is presented for solving nonlinear elastic large deformation problems. To obtain the formulae of the IEFG method for elastic large deformation problems, we use the Galerkin weak form to obtain the discretized system equation, and use the penalty method to apply the displacement boundary conditions. Some selected numerical examples of two-dimensional elastic large deformation problems are given, and the numerical results are analyzed. From the examples, it is shown that the IEFG method in this paper has higher computational precision than the element-free Galerkin (EFG) method presented before.

The influence of pressure on the structural and elastic properties of ScM ($\mathrm{\text{M}}=\mathrm{\text{Rh}}$, Cu, Ag, Hg) compounds has been investigated by using ab initio approach pseudopotential plane-wave method based on the density functional theory within the generalized gradient approximation (GGA). The optical properties have been investigated under zero pressure. It is found that the optimized lattice parameters for all metals are in good agreement with the experimental data and other available theoretical values. We obtained three independent elastic constants $C_{ij}$ ($C_{11},C_{12}$ and $C_{44}$) and various elastic parameters such as bulk modulus $B$, shear modulus $G$, Young’s modulus $E,B/G$, Poisson’s ratio $\nu$ and anisotropy factor $A$ as a function of pressure. In addition, the mechanical stability and ductile/brittle nature are also investigated from the calculated elastic constants. The study of optical properties reveals that all of these compounds possess good absorption coefficient in the high energy region and the refractive index of all these compounds is higher in the low energy region and gradually decreased in the high energy region. All these calculations have been carried out using the CASTEP computer code.