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[en] In this paper, the implementation of an interface element to model the contact between the core and the layer in thermoelastic contact analysis of monolayer pressure vessels is presented. How to couple the elements of the core and the layer and implementation of the boundary conditions are also described. The source of heat could be due to temperature difference in the layers in practice or the heat due to welding in the concentrated welding zone of the layer during the assemblage of the layer and the core of the pressure vessel. Thermoelastic contact between the core and layer has come under investigation. It is concluded that the methodology with the special employment of interface elements in joints and contact region is efficient for analysis of joints and contact problems in the analysis of layered media
[en] In this paper a boundary element formulation for heat conduction problems are presented. The different types of boundary conditions of condution, convection and radiation are included in the integral equations. The transient fundamental solution is used and by considering small time limits the integration over the time domain are calculated analytically. In the absence of a radiation boundary condition a set of linear system of equations would be developed. While, in the presence of radiation boundary conditions, a set of nonlinear system of equations is resulted. Also presented in this paper a multi-region boundary element analysis for heat conduction problems composed of different materials having different thermal properties. The compatibility and equilibrium are used to link the systems of equations developed for each region. Examples are provided to check the accuracy of the method and the implementation. (orig.)
[en] In this study, particulate-reinforced aluminum matrix composites were prepared by incorporation of 10 and 20 vol.% of copper. The metal matrix composite samples were fabricated using cold spray deposition technique. In general, the global properties of cold sprayed deposited materials are different from those of conventionally processed. This paper investigates mechanical properties of cold sprayed composites using available theoretical and experimental techniques. In order to determine the mechanical properties, both numerical simulation and analytical method were conducted. The microhardness and elastic modulus of Al–Cu cold spray coating were also determined using the Knoop hardness technique. Due to the different mechanical properties in transverse and longitudinal directions, the Knoop hardness was applied in both directions on the cross section of coatings. Image based numerical simulation was also performed on both transverse and longitudinal directions. Comparison between the results from the analytical models, experimental techniques, and numerical simulation helped us to better understand the influence of microstructural characteristic on the mechanical properties of cold spray deposited metal matrix composite.
[en] A first endeavor to exploit the differential quadrature element method (DQEM) as a simple, accurate and computationally efficient numerical tool for the shape optimization of convective-radiating extended surfaces or fins is made. The formulations are general so that the spatial and spatial-temperature dependent geometrical and thermal parameters can easily be implemented. The thermal conductivity of the fin is assumed to vary as a linear function of the temperature. The effects of a convective-radiative condition at the fin tip and effective convective condition at the fin base are considered. The optimization of fins with uniform and step cross-sections is investigated. The accuracy of the method is demonstrated by comparing its results with those generated by Adomian's decomposition technique, Taylor transformation technique and finite difference method. It is shown that, using few grid points, highly accurate results are obtained. Less computational effort of the method with respect to the finite difference method is shown
[en] Based on the three-dimensional elasticity theory, free vibration analysis of functionally graded (FG) curved thick panels under various boundary conditions is studied. Panel with two opposite edges simply supported and arbitrary boundary conditions at the other edges are considered. Two different models of material properties variations based on the power law distribution in terms of the volume fractions of the constituents and the exponential distribution of the material properties through the thickness are considered. Differential quadrature method in conjunction with the trigonometric functions is used to discretize the governing equations. With a continuous material properties variation assumption through the thickness of the curved panel, differential quadrature method is efficiently used to discretize the governing equations and to implement the related boundary conditions at the top and bottom surfaces of the curved panel and in strong form. The convergence of the method is demonstrated and to validate the results, comparisons are made with the solutions for isotropic and FG curved panels. By examining the results of thick FG curved panels for various geometrical and material parameters and subjected to different boundary conditions, the influence of these parameters and in particular, those due to functionally graded material parameters are studied.