Lutsk National Technical University

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Pasternak I.,Lutsk National Technical University | Pasternak R.,Lutsk National Technical University | Sulym H.,Bialystok Technical University
Engineering Analysis with Boundary Elements | Year: 2013

This paper develops Somigliana type boundary integral equations for 2D thermoelectroelasticity of anisotropic solids with cracks and thin inclusions. Two approaches for obtaining of these equations are proposed, which validate each other. Derived boundary integral equations contain domain integrals only if the body forces or distributed heat sources are present, which is advantageous comparing to the existing ones. Closed-form expressions are obtained for all kernels. A model of a thin pyroelectric inclusion is obtained, which can be also used for the analysis of solids with impermeable, permeable and semi-permeable cracks, and cracks with an imperfect thermal contact of their faces. The paper considers both finite and infinite solids. In the latter case it is proved, that in contrast with the anisotropic thermoelasticity, the uniform heat flux can produce nonzero stress and electric displacement in the unnotched pyroelectric medium due to the tertiary pyroelectric effect. Obtained boundary integral equations and inclusion models are introduced into the computational algorithm of the boundary element method. The numerical analysis of sample and new problems proved the validity of the developed approach, and allowed to obtain some new results. © 2012 Published by Elsevier Ltd.


Pasternak I.,Lutsk National Technical University | Sulym H.,Bialystok Technical University
Engineering Analysis with Boundary Elements | Year: 2013

This paper presents a novel approach for obtaining boundary integral equations of 2D anisotropic magnetoelectroelasticity. This approach is based on the holomorphy theorems and the Stroh formalism and allows developing of the integral equations for the aperiodic, singly and doubly periodic problems of magnetoelectroelasticity. Obtained equations contain the unknown discontinuities of displacement, electric and magnetic potentials and also traction, electric displacement and magnetic induction that allow adopting the existing boundary element procedures for their solution. Analytical solutions for systems of collinear permeable or impermeable cracks are obtained. Numerical boundary element solutions are obtained for the singly and doubly periodic sets of permeable and impermeable cracks in the magnetoelectroelastic medium and a half-plane. Comparison with analytical solutions and other available results validate the present formulations and numerical computation. © 2012 Elsevier Ltd.


We present the results of investigations of the influence of the composition of mixture on the relative abrasive wear resistance of a material of the Ti–Fe–C–B–Cr system obtained by self-propagating hightemperature synthesis. It is shown that, as a result of the addition of carbon and boron, the heterogeneity of the structure and its wear resistance increase. It was discovered that, as a result of the formation of the optimal composition of mixtures and the attainment of lower porosities of materials, it is possible to guarantee the highest tribological characteristics. © 2016 Springer Science+Business Media New York


Swic A.,Lublin University of Technology | Zubrzycki J.,Lublin University of Technology | Taranenko V.,Lutsk National Technical University
Applied Mechanics and Materials | Year: 2013

The specifics of modelling the dynamic system of turning as well as straight and plunge grinding of low rigidity shafts is presented in the paper. Methodology of developing models while machining shafts in elastic-deformable condition is shown. The specifics of processing of low rigidity elements is taken into account by introducing equations of constraint reflecting additional elastic strain in equation describing the control force effect. Systemic analysis of the developed models is performed and main hierarchical structure levels are given. © (2013) Trans Tech Publications, Switzerland.


Zubrzycki J.,Lublin University of Technology | Swic A.,Lublin University of Technology | Taranenko V.,Lutsk National Technical University
Applied Mechanics and Materials | Year: 2013

In the paper, we discuss the mathematical modelling and optimal control of hole drilling. The drilling feed is considered to be a control action, while the cutting force is a controlled variable. Transfer functions of the regulators were obtained, with the cutting force variance used as a quality criterion for the automatic control system. The paper also presents problems connected with the structure of a typical automated process for designing a hole drilling operation. A block diagram of a typical automated process for designing hole drilling operations was introduced. The processed algorithms for setting regulator parameters according to a priori technological information and program protection were also introduced, which allowed for automation of the process study of the automatic control system for hole drilling operations. © (2013) Trans Tech Publications, Switzerland.


Luniov S.V.,Lutsk National Technical University
Journal of Nano- and Electronic Physics | Year: 2015

The electron scattering in the (L1 - Δ1) model of the conduction band of n-Ge single crystals formed by uniaxial pressure along the crystallographic direction [100] has been investigated. Obtained experimental results and performed theoretical calculations show that nonequivalent intervalley electron scattering between L1 and Δ1 minima becomes significant for the range of uniaxial pressures from 1.4 to 2.3 GPa and the relative contribution of this scattering depends on the magnitude of the uniaxial pressure. The presence of the maximum for the dependences of the Hall coefficient on the uniaxial pressure for P ~ 2.1 GPa, when the energy gap between L1 and Δ1 "is closed", is explained by greatest efficiency of the given scattering mechanism for such pressures. © 2015 Sumy State University.


Pasternak I.,Lutsk National Technical University
Engineering Analysis with Boundary Elements | Year: 2011

This paper develops integral equations and boundary element method for determination of 2D electro-elastic state of solids containing cracks, thin voids and inclusions. It proves that stress and electric displacement field near the tip of thin inhomogeneity possesses square root singularity. Thus, for determination of electromechanical fields near thin defects new special base functions are introduced. The interpolation quadratures along with the polynomial transformations are adopted for efficient numerical evaluation of singular and hypersingular integrals. Presented numerical examples show high efficiency and accuracy of the proposed approach. © 2010 Elsevier Ltd.


Shvedyk M.,Lutsk National Technical University
INMATEH - Agricultural Engineering | Year: 2016

In the article the studies of crop losses causes during harvest are presented. It is established that a significant cause of grain loss is a non-simultaneous ripening in the wheat. Thus, during reel bats impacts on stalks, the largest and most valuable grains that ripen earliest are knocked out of the wheat and fall to the ground. It is established that these losses are significant and irreversible. The current technical condition of combine harvesters cannot eliminate these losses. To eliminate these losses, a new design of pneumatic collector has been proposed in the article. The principle of its work is based on the vacuum created. Due to the vacuum, the grains that were knocked out from the wheat by reel bats are sucked and sent into the cyclone.


Pasternak I.,Lutsk National Technical University
Engineering Analysis with Boundary Elements | Year: 2012

A two-dimensional boundary element method for the analysis of a magnetoelectroelastic medium containing doubly periodic sets of cracks or thin inclusions is developed in this paper. The integral equations and closed-form expressions for corresponding kernels are obtained. Based on the quasi-periodicity of extended displacement and stress function, the integral representations for average stress, strain, electric displacement, magnetic induction etc. are developed. The algorithm of effective properties determination is given. The numerical examples prove the efficiency and high accuracy of the proposed approach in determination of stress, electric displacement and magnetic induction intensity factors and effective properties of the material containing doubly periodic arrays of cracks or thin inclusions. © 2011 Elsevier Ltd. All rights reserved.


Pasternak I.,Lutsk National Technical University
Engineering Analysis with Boundary Elements | Year: 2012

This paper develops the Somigliana type boundary integral equations for fracture of anisotropic thermoelastic solids using the Stroh formalism and the theory of analytic functions. In the absence of body forces and internal heat sources, obtained integral equations contain only curvilinear integrals over the solid's boundary and crack faces. Thus, the volume integration is eliminated and also there is no need to evaluate integrals over the contours in the mapped temperature domain as it was done before. In addition to finite solids, the case of an infinite anisotropic medium with a remote thermal load is also studied. The dual boundary element method for fracture of anisotropic thermoelastic solids is developed based on the obtained boundary integral equations. Presented numerical examples show the validity and efficiency of the obtained equations in the analysis of both finite and infinite solids with cracks. © 2012 Elsevier Ltd. All rights reserved.

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