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Showing papers by "Ternopil Ivan Pul'uj National Technical University published in 2014"


Journal ArticleDOI
TL;DR: In this article, the effect of hydrogen absorbed by metal on the variation of the structure and mechanical properties of the main gas pipeline after a long-term operation is found. But the main regularities in the graded nature of the static deformation process and the impact of hydrogenation on the scattered damage and fracture accumulation are found.
Abstract: The effect of the in-service scattered damage in the pipe wall metal is evaluated, and the effect of hydrogen absorbed by metal on the variation of the structure and mechanical properties of the main gas pipeline after a long-term operation is found. The main regularities in the graded nature of the static deformation process and the effect of hydrogenation on the scattered damage and fracture accumulation are found.

26 citations


Journal ArticleDOI
TL;DR: In this paper, the correlation of microstructure, temperature and Charpy V-notch impact properties of a steel 17G1S pipeline steel was investigated, where the dynamic failure of specimens is represented as a successive process of the loss of shear stability, which takes place at different structural/scale levels of the material.
Abstract: The correlation of microstructure, temperature and Charpy V-notch impact properties of a steel 17G1S pipeline steel was investigated in this study. Within the concept of physical mesomechanics, the dynamic failure of specimens is represented as a successive process of the loss of shear stability, which takes place at different structural/scale levels of the material. Characteristic stages are analyzed for various modes of failure, moreover, typical levels of loading and oscillation periods, etc. are determined. Relations between low temperature derived through this test, microstructures and Charpy (V-notch) toughness test results are also discussed in this paper.

25 citations


Journal ArticleDOI
TL;DR: In this paper, the mechanisms of metal damage in the pipe of the main pipeline are investigated, the main reasons for their appearance are found and analysed, and the main results are obtained by joint use of metallography, indentation, method for processing and analysis of digital images.
Abstract: The mechanisms of metal damage in the pipe of the main pipeline are investigated, the main reasons for their appearance are found and analysed. The main results are obtained by joint use of metallography, indentation, method for processing and analysis of digital images.

21 citations


Journal ArticleDOI
TL;DR: In this article, the authors investigated the reasons and mechanisms of wear of the hinge-lever tilting mechanism bearings of the continuous billet casting machine mold operating in the rolling motion mode.
Abstract: The results are considered of the investigations into the reasons and mechanisms of wear of the hinge-lever tilting mechanism bearings of the continuous billet casting machine mold operating in the rolling motion mode. The types of defects of the outer and inner rings of the bearing are determined, as well as their shape and relative position. The optical and electron- microscopic analysis of the surface of the defect is performed. It is established that the static and dynamic loading parameters have a significant effect on the mechanisms of friction and wear, as well as on the formation of dents in the bearing races. The results obtained allow assessing the reasons for wear of the hinge-lever tilting mechanism bearings, and laying the ground for the development of the technique for their elimination or minimization.

7 citations


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 Article
TL;DR: In this paper, the authors present a Verilog-AMS model of the comb-drive sensing element of the integrated capacitive microaccelerometer, which allows to simulate the reaction of the sensing element effected by the applied force of acceleration.
Abstract: The article presents Verilog – AMS model of the comb-drive sensing element of the integrated capacitive microaccelerometer. The suggested model allows to simulate the reaction of the sensing element effected by the applied force of acceleration, changes of its comb-drive capacities, output voltages and currents for determining its constructive parameters and for analysis of the mechanical module of the integrated device at the behavioral level of computer-aided design.

2 citations


Journal ArticleDOI
TL;DR: In this paper, the authors performed digital identification and evaluation of the kinetics of damage accumulation on the surface of a fatigue sensor using digital image processing, where the main features in the development of shear processes were identified by consistent processing of surface damage data.
Abstract: Digital identification and evaluation of the kinetics of damage accumulation on the surface of a fatigue sensor are performed using digital image processing. Damage accumulation is evaluated from the results of diagnosis of individual stages of cyclic deformation. It is found that the different stages of damage correspond to particular image parameters. The main features in the development of shear processes were identified by consistent processing of surface damage data. Theoretical background and experimental results are presented.

2 citations


Journal ArticleDOI
TL;DR: In this paper, the influence of electrolytical hydrogenation on fracture toughness, corrosion crack-growth resistance and fracture micromechanisms of operated 12Cr1MoV steel of thermal power plant superheater collector has been studied.

2 citations


Journal ArticleDOI
TL;DR: In this article, equipment and technology for induction surfacing of thin flat components, including disc-shaped components, with a thickness of 3-6mm using thermal and electromagnetic screens, vibration and also centrifugal rotational forces are described.
Abstract: Equipment and technology for induction surfacing of thin flat components, including disc-shaped components, with a thickness of 3–6 mm using thermal and electromagnetic screens, vibration and also centrifugal rotational forces are described. The advantages of these systems in comparison with the currently available surfacing technologies which do not use the above additional technological operations are described.

2 citations


Journal ArticleDOI
TL;DR: In this paper, the formation of strain induced relief, as well as the cracking pattern of modified surface layer are illustrated by methods of optical microscopy and interferential profilometry and changes to occur in subsurface layer are characterized by means of nanoindentation and scanning electron microscopy of fracture surfaces.
Abstract: Cyclic tension and alternating bending tests of 12Cr1MoV and 30CrMnSiNi2 steels specimens in as–supplied state and after surface irradiation by Zr+ ion beam have been carried out. Distinctions in formation of strain induced relief, as well as cracking pattern of modified surface layer are illustrated by methods of optical microscopy and interferential profilometry. Changes to occur in subsurface layer are characterized by means of nanoindentation and scanning electron microscopy of fracture surfaces. The description of differences of deformation behavior is carried out with use of the multiple cracking concepts.

1 citations


Journal ArticleDOI
TL;DR: In this article, the limit state of a boiler steam superheater collector model was assessed using failure assessment diagram (FAD) and the critical sizes of the inner surface defect that is perpendicular to the axis of the cylinder, considering fracture toughness of 12Cr1MoV steel for static and cyclic loading, were assessed.

Journal ArticleDOI
TL;DR: Using the scanning electron microscopy data the main regularities of the fatigue crack propagation in the 17Mn1Si steel were studied in this article, based on fracture surface observation and analysis one can testify that the transition of the leading role of deformation and failure from lower structural level to the higher one has the ordered pattern.
Abstract: Using the scanning electron microscopy data the main regularities of the fatigue crack propagation in the 17Mn1Si steel were studied. Based on fracture surface observation and analysis one can testify that the transition of the leading role of deformation and failure from the lower structural level to the higher one has the ordered pattern.