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Ternopil Ivan Pul'uj National Technical University

About: Ternopil Ivan Pul'uj National Technical University is a based out in . It is known for research contribution in the topics: Deformation (engineering) & Fracture toughness. The organization has 134 authors who have published 187 publications receiving 1019 citations.


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Proceedings ArticleDOI
03 Oct 2014
TL;DR: In this article, the authors proposed to estimate the accuracy of the hydrocylinder cross-section shapes based on the analysis of the circle diagram of their inner cylindrical surfaces formed by the manufacturing operations, such as rough and semi-finishing boring and finishing paying-out, taking advantage of the method of deflection approximation from the circle by the Fourier's trigonometric series in the gap.
Abstract: It was proposed to estimate the accuracy of the hydro-cylinder cross-section shapes basing on the analysis of the circle diagram of their inner cylindrical surfaces, formed by the manufacturing operations, such as rough and semi-finishing boring and finishing paying-out, taking advantage of the method of deflection approximation from the circle by the Fourier’s trigonometric series in the gap [0, 2π].Characteristics of the deflection dispersion of the radius-vector as the random value (average value, dispersion, amplitude spectrum) have been obtained for every circle diagram separately. It is proposed to present these characteristics as random values.Dependences for finding mathematic expectation and dispersion for the lot of parts, machined at every of the available manufacturing operation, have been obtained for certain number of samples and circle diagrams, taking advantage of the small sampling theory, the method of rectangular engagement in particular.The effectiveness of manufacturing operations has been estimated according to the Student and Fisher t-test. Availability of the advantageous or disadvantageous manufacturing heredity of the hydrocylinder cross-section shape has been found.As the result of carried out experimental investigations and processing of the obtained statistic data on the inner cylindrical surface of the truck hoist crane hydrocylinder KTA-25, produced by the company “Drogobych truck crane plant” (Ukraine), the need to improve the manufacturing operation of the semi-finishing boring has been analysed.Copyright © 2014 by ASME

6 citations

Journal ArticleDOI
TL;DR: In this paper, the metal-insulator transition in a generalized Hubbard model with correlated hopping at half-filling and zero temperature was studied and the expressions for energy gap width and the concentration of polar states (holes or doublons) were obtained.
Abstract: In the present paper metal-insulator transition is studied in a generalized Hubbard model with correlated hopping at half-filling and zero temperature. Single-particle Green function and energy spectrum of electron system are calculated. The expressions for energy gap width and the concentration of polar states (holes or doublons) are obtained. The conditions for metallic and insulating states are found.

6 citations

Proceedings ArticleDOI
01 Sep 2018
TL;DR: The paper presents the axiomatic-deductive strategy of organizing the contents of the academic discipline using the ontological approach, which enables an effective system solution for a wide range of important methodological, methodical and technological tasks for the development of intellectualized systems of electronic learning in the field of information technologies.
Abstract: The paper presents the axiomatic-deductive strategy of organizing the contents of the academic discipline using the ontological approach., which enables an effective system solution for a wide range of important methodological, methodical and technological tasks for the development of intellectualized systems of electronic learning in the field of information technologies. In particular, it was noted that the axiomatic-deductive strategy of the organization of educational content ensures the presence of a clear, compact, ordered structure of knowledge organization about the subject area of academic discipline and is well consistent with the theoretical formal basis for the development of modern ontologies - a family of descriptive logics. As an example of the application of the proposed axiomatic-deductive strategy, elements of the glossary and taxonomy of concepts of the discipline “Computer Logic” have been developed, that is embodied in the Protegee environment using the OWL ontology description language. On the basis of the developed glossary and taxonomy of the primary concepts, basic axiomatic statements are formulated and the derivative concepts of the discipline “Computer Logic” are defined, which is the basis for organizing its content.

5 citations

Journal ArticleDOI
TL;DR: In this paper, the effect of cold expansion on the stress state and fatigue durability of aluminum plates with functional holes under uniaxial cyclic loading was studied and the results showed that cold expansion degree of 1% increases the lifetime of the plates to the initiation of fatigue crack length of 0.25 mm in 1.5-3 times as compared with plane plates.
Abstract: Analysis of the literature shows that in some cases existing technological methods of processing, including cold expansion, are the effective means to improve fatigue durability of structural elements with holes. The effect of cold expansion (1−3 %) on the stress state and fatigue durability of aluminum plates with functional holes under uniaxial cyclic loading was studied. The fatigue crack growth in the plates with a thickness t = 6 mm and width of 60 mm with a central hole diameter of 8 mm and 10 mm of aluminum alloy D16chТ (2024-T3) was investigated. Fatigue test was carried out under constant amplitude loading at stress ratio R = σ min /σ max = 0 and room temperature. Here σ min , σ max are the minimum and maximum stresses, respectively. The stress range was 147 MPa, loading frequency was 25 Hz. The mechanical properties of the alloy at room temperature were: yield strength σ Y = 300 MPa, tensile strength σ U = 430 MPa. For all tested specimens with cold expanded holes the cracks initiation from the edges of holes on the entrance faces mandrel and from middle part for plain hole. Using the finite element method, the distribution of local residual stresses in the vicinity of the expanded hole was calculated. For specimens with cold expanded holes the least compressive stresses were near the entrance face and the largest were in the middle of the hole and near the exit face. With the increase of the cold expansion hole, the difference in values of compressive residual stress along the plate thickness is reduced. The width zone of residual compressive stresses increase with the increase of cold expansion. The dependencies of the number of cycles to crack initiation in aluminum specimens on the local maximum stress and local stresses range in the vicinity of surface hole were obtained. Cold expansion degree of 1% increases the lifetime of the plates to the initiation of fatigue crack length of 0.25 mm in 1.5-3 times as compared with plane plates. A similar dependence is observed for cold expansion of 2%. With further increase of cold expansion degree up to 3% the lifetime to fatigue crack initiation is increased in 7−10 times as compared with plane plate. By using the finite element method, the distributions of local stress range, maximum and minimum local stress near the hole depending on the number of loading cycles and cold expansion were built. In the middle section of the specimen the local stress ratio in the second half-cycle of load decrease with increasing of distance from the edge of the hole and with the increase of cold expansion. The lowest value of local stress ratio was obtained at cold expansion degree of 3% and it is constant across thickness of plate.

5 citations

Journal ArticleDOI
TL;DR: In this paper, a single-lap adhesive joint of S235JR steel sheet was formed on two types of substrates: with or without corrosion products on the surface, and the surface of steel sheet adherends was pre-treated with three cleaning solutions: acetone, Wiko industrial degreasing agent and Cortanin F anti-corrosion agent, depending on the state of the surface.
Abstract: The following paper analyses selected problems regarding the impact of technological parameters and the type of adherend material on the strength of adhesive-bonded steel sheet joints. The subject of the test was a single-lap adhesive joint of S235JR steel sheet. Joints were formed on two types of substrates: with or without corrosion products on the surface. The surface of steel sheet adherends was pre-treated with three cleaning solutions: acetone, Wiko industrial degreasing agent and Cortanin F anti-corrosion agent, depending on the state of the surface. Adhesive joints were formed with Epidian 53/ET/100:15 epoxy adhesive. The formed joints were subjected to one of three ageing variants: 14 days, two months and 3 months, which were followed by destructive testing to determine the shear strength of joints. The analysis of results obtained in the tests indicates that the strength performance of adhesive joints of corrosion-free adherends was characterised by higher values than in corroded steel sheets, regardless of ageing time.

5 citations


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Performance
Metrics
No. of papers from the Institution in previous years
YearPapers
20213
202010
201919
201819
201736
201632