Papers by Keyword: Discretization

Abstract: This work concerns the numerical modeling of stationary conduction heat transfer in a 3D three-dimensional anisotropic material subjected to an internal heat source, based on the finite element method MEF and using the Galerkin method. The field of study is a cube representing the seven crystalline systems subjected to an internal heat source and convective boundaries. The obtained equation system is solved by the LU method. The automatic mesh is managed for all the domain nodes via the program which we have written in FORTRAN language. This program allowed temperature field calculation and was applied for different crystalline systems: monoclinic, triclinic, orthorhombic, trigonal, cubic that are identified by their thermal conductivity tensors [kij]. The obtained temperature profiles obtained are in accordance with heat transfer theory and clearly illustrate the crystalline structure symmetry; this calculation permits to predict the possible thermal deformations in an anisotropic solid.

Abstract: The aim of the paper is to inform about main features of Non-linear Normal Modes (NNM) as a powerful tool for investigation of multi-degree of freedom (MDOF) dynamic systems. In particular, it is shown how this concept can be used to investigate forced resonances of non-linear symmetric systems including non-linear localization of vibrational energy. NNMs can provide a valuable tool for understanding essentially non-linear dynamic phenomena having no counterparts in linear theory and which do not enable analysis using linearized procedures. Discrete MDOF systems are considered in this study. A couple of possible approaches are outlined together with some demonstrations of numerical results.

Abstract: The study of the bending vibrations of Euler-Bernoulli beams is typically performed based on pure elastic material models, which neglect the damping. However, in practice, due to the internal friction of the material, the vibrations are damped. This phenomenon can be taken into account by using a viscoelastic material model, in which supplementary strains, dependent on the strain rates, are considered. In the paper, free bending vibrations of homogeneous viscoelastic Euler-Bernoulli beams are studied by developing generalized forms of an exact and of an approximate method, respectively, used regularly in the study of pure elastic Euler-Bernoulli beams. The developed methods are applied and compared on a numerical example, highlighting their advantages and limitations.

Abstract: In five-axis tool path planning, interference between the cutting tool and parametric surface is very critical. One way of doing interference detection is first to discretize the surface. In this article we develop a new approach to discretize parametric surface adaptively by applying curvature sphere. Layer by layer the original surface is discretized into triangle meshes bases on the polyline between the triangulated and un-triangulated areas of the surface. Triangles generated with our method are adaptive, which means the density of the triangles changes with the local curvature value of the surface. We also develop a method to deal with triangle meshes overlapping problem. So triangle meshes generated with our algorithm is without gaps or any overlapping problem. Finally a criterion is suggested when the generation should stop. The algorithm has been tested for some parametric surfaces and the result turns out to be satisfactory.

Abstract: In order to solve the problem of continuous attribute discretization, a new improved SOM clustering algorithm was proposed. The algorithm uses the SOM to achieve the initial cluster and get the clustering up limit, then treats the initial cluster centers as samples and use the BIRCH hierarchical clustering algorithm to get secondary clustering, then solves the problems of inflated clusters and identifies discrete breakpoints set. Finally, find the nearest neighbors of each cluster center among these any samples of Breakpoints sets which belong to its attribute, and use it as a basis of discrete trimming. The experimental results show that the proposed algorithm outperforms the conventional discrete SOM clustering algorithm in the breakpoints set (contour factor to enhance 75%) and discrete accuracy (incompatible degrees closer to 0) aspects.

Abstract: The performance of an Earth-Air Heat Exchanger (EAHE) system to be operated in climatic and soil conditions prevailing in the Indian district of Nagpur is modeled numerically. To do so, a CFD model is developed in ANSYS Fluent 12.1. The validation of the CFD model is carried out using data obtained from published literature and good agreement is established between the simulation results and published experimental data. An earth pipe of length 60 m and internal diameter 0.1 m is chosen for validating the model and this validated model is used to further investigate for three different lengths of the pipe - 40 m, 35 m and 30 m. The 3-dimensional flow field through the earth air heat exchanger is studied numerically by solving the appropriate governing equations namely: continuity, momentum and energy equations and a finite volume CFD code is employed for solving the same. An air inlet velocity of 2 m/s is maintained and the inlet temperature was varied between 308.1 K and 315 K for each chosen length. The decrease in temperature and flow distribution along the pipe length is plotted.

Abstract: when the rough set be used to deal with Knowledge representation system, the data in decision table should be expressed in discrete data, if some conditions or decision attribute is continuous value, which should be discrete Before process.Discretization is not specific data processing only by rough set theory , people have conducted extensive research on discretization problem before the rough set theory put forward , and Made a lot of progress ,but the discretization technique is can not be completely in common used in every subject, different areas have their own unique requirements and handling .This paper proposes a discretization algorithm based on regular conditional entropy.

Abstract: Based on the original CAV formula definition given by the electric power research institute in the United States, the continuous integral formula is discretized so that it can be better applicable to the actual application requirements, and also the shaded area calculation method necessary in the process of calculation is further proposed. Finally, this algorithm is implemented with LAVIEW program, and also the simulation data and the CAV calculation result of the real Lushan earthquake acceleration data were given so that the algorithm was fully validated, and also a solid foundation was further laid for the deeper CAV-related parameter study.

Abstract: The textile industry is represented not only by fashion (most popular area) but also textile material for industrial purposes. The very old use of textile materials is production of fabric bags. The deformation of such bag is the subject of computer modeling, what is the contents of the paper. The deformation of the 2D cloth layer, exposed to normal pressure, has the mathematical description in the form of the partial differential equation. The solution depends on the area, on which is searched, and on the boundary conditions. It is known only for planar circular area. The deformation of more complicated shapes (3D) must be found using computer simulations. The problem, discretized by finite element method, has the form of the system of algebraic equations. The description has non-linear character and brings a range of problems. The solution possibilities are described in the paper. Finally the solution of the 3D problem is shown.

Abstract: This text apply UG software to the design and study on the type parameter of the brakes. On the basis of the principles of discretization, discretize the structural pattern of the brake drum. select the typical characteristic of the brake assemblies and the individual parts of the 3d parameterization modeling work, to build a model for parameterization library calls.