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A static analysis of circular and elliptic Kirchhoff plates resting on internal elastic supports by the Boundary Element Method is presented in the paper. Elastic support has the character of Winkler-type elastic foundations. Bilateral and unilateral internal constraints are taken into consideration. The Betti’s theorem is used to derive the boundary domain integral equation. The direct version of...
The paper examines the problem of the influence of restrictions on freedom of horizontal displacements in thermally loaded sandwich beams. The classical theory of sandwich beams and panels with thin facings and a soft core has been applied. It was assumed that the cross-section of the beam could be asymmetric geometrically and materially. The beam has vertical supports and additional horizontal supports...
In this paper, the results obtained from five models of the solidification with substitute thermal capacity were compared. The calculations were carried out for steel containing 0.35% carbon with using an in-home solver based on the finite element method (FEM). A comparison was made on the base of analysis of the cooling curves at selected nodes.
The paper is devoted to an application of the immune algorithm and the finite element method for generation of 3D structures using two different types of parameterization and comparing the final results. The shape, topology and material of the structure are generated for optimization criterion like minimum of the mass of the structure. Two different interpolation functions like: multinomial interpolation...
We consider a M2θ/G/1/m queueing system with arrival of customer batches, which uses a threshold control mechanism of the service time and arrival rate. The system receives two independent flows of customers, one of which is blocked in an overload mode (under the condition that the number of customers in the system exceeds a given threshold value h). Full blocking of the input flow is carried out...
The paper raises the problems connected with the durability of ceramic elements used in technology. It presents mathematic - statistic methods defining the influence of stress on ceramic elements durability. The paper also contains the results of numerical analysis carried out by the Finite Elements Method in the ADINA system, considering a ceramic elements. The above analysis is confirmed and proved...
The sensitivity analysis of the transient temperature field in the 2D tissue domain with respect to its thermophysical parameters is discussed. In particular, the influence of tissue specific heat, thermal conductivity, perfusion rate and metabolic heat source on the temperature distribution is considered. In order to determine the influence of variations of these parameters on temperature distribution,...
In this paper we present an application of the system of two homogeneous linear recurrence equations to evaluate the determinant of pentadiagonal matrix. The general considerations are illustrated by two examples. It is shown that the proposed approach is suited for implementation using computer algebra systems.
After a brief review of (slowly converging) Wallis-type infinite products for π , (faster converging), Dido-type infinite products for π are treated. The notion of “alternating products” facilitates error checking.
In this paper the 2D heterogeneous tissue domain (forearm cross-section) insulated by a layer of protective clothing is considered. The aim of considerations is to develop an algorithm simulating the tissue heating process resulting from the sudden change of external boundary conditions. Here, the authors exploit a certain version of the control volume method (CVM) using the Voronoi tessellation....
In the paper the influence of the eigenvalues of the matrix on the stability of the numerical simulations of binary alloy solidification process was analyzed. One step Θ scheme time integration for the modeling was used. The occurrence of the equation clotting full, diagonal and lumped capacitance matrix was considered. In the explicit schema (conditionally stable) the major influence on the proper...
The article is a continuation of the considerations on the three-dimensional Fourier equation supplemented by the third boundary condition (the Robin’s condition). The paper is based on the Finite Difference Method.
This paper presents a simulation of the casting solidification process performed on graphics processors compatible with nVidia CUDA architecture. Indispensable for the parallel implementation of a computer simulation of the solidification process, it was necessary to modify the numerical model. The new approach shown in this paper allows the process of matrix building to be divided into two independent...
Using analytical methods we obtain the integral representation of a two-parameter Feller semigroup on a closed interval [r1, r2] corresponding to such a diffusion phenomenon that sticking, partial reflection, absorption and jump phenomena occur at the endpoints r1, r2 and at some interior point r ∈ (r1,r2).
Investigation of the closed three-level HM-network, which is the model of the production transportation in a logistic transport system, is conducted in this article. The approximated expression for the expected income of the central system and the system of the nonhomogeneous differential equations for an average number of messages in network systems, when the incomes from transitions between network’s...
This paper is focused on the process of computing First Sets. The First Sets are used to build structures which control a syntax analyser (also known as parser). Three methods of creating First Sets were compared in terms of execution time. The first method is known sequential algorithm and the author’s own methods are concurrent computing sets for each non-terminal symbol (called the CEN method)...
The object of this research is an open queueing G-network with signals with random delay. The purpose of the research is investigation of such a network at the transient behavior. It is considered the case when the intensity of the incoming flow of positive and negative messages and service intensity of messages do not depend on time. All the systems in the network are one-line. It is described the...
In this paper, derivation of the Green’s function for the heat conduction problems in a finite multi-layered hollow cylinder is presented. Formulation and solution of the problem includes an arbitrary number of the cylinder layers characterized by various thermal properties. At the interfaces perfect thermal contact was assumed. The Green’s function for the three-dimensional heat conduction problems...
This paper concerns numerical modelling of the Yb:YAG laser beam welding process. Numerical algorithms are developed for the analysis of thermal phenomena in a laser welded joint taking into account the motion of the liquid material in the welding pool. The model describing the laser beam heat source power distribution is developed on the basis of the kriging method. The heat source model uses the...
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