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VOLUME 42, № 4, 2006 (July - August)


Ostash O. P., Andreiko I. M., and Holovatiuk Yu. V. Materials degradation and fatigue life time of aviation constructions after durable service

SUMMARY. The residual life-time estimation for aircraft components after long-term exploitation is considered. Results of static and fatigue tests in air and in 3% NaCl solution for as–received Д16T type aluminum alloys and after model and in-service degradations are presented. The characteristics sensitivity to long-term material degradation is determined. An approach and correction coefficients for the assessment of aircraft component fatigue life-time taking into account the materials degradation are considered.

Dmytrakh I. M., Bilyi O. L., Kolodii B. I., and Leshchak R. L. Assessment of the development of localized corrosion damages of welded joints of HPP water-steam supply path elements s

SUMMARY. The calculation method has been proposed and prediction assessments of the maximum depth of corrosion damaging of welded joint components of dissimilar pipes have been done. This method is grounded on the basic electrochemical parameters of materials of welded joints obtained by standard potentiometric techniques and also on numeric-analytical procedure of determining corrosion current density on the internal pipe surface, which considers the given welded joint as a three-electrode electrochemical system.

Student O. Z., Markov A. D., and Nykyforchyn H. M. Peculiarities of hydrogen effect on the properties and fracture mechanisms of welded joints metal of HPP steam pipelines

SUMMARY. The tensile mechanical properties of exploited of about 2•105 h and model (repair) welded joints of steam pipeline were investigated. As a result of service degradation of a weld metal (WM) its strength decreases to compare to the base metal (BM). It is shown that unregulated specimens direction along a weld joint axis is the best for revealing the weld metal degradation. The use of cathode polarization makes it easier to assess the degraded metal state and enables us to estimate the BM state, which is impossible during air testing. Peculiarities of internal (preliminary hydrogenation) and external (electrolytic hydrogenating during testing) hydrogen effect on the properties and fracture mechanisms of WM are found.

Balytskyi O. I., Ripei I. V., and Protsakh Kh. A. Reliability of HPP steam pipelines during long-term operation

SUMMARY. The relation can be considered as a recommended parameter of the degree of material softening and termination of the refractory resource of stream pipelines of HPP. It has been established that in the steam pipelines with increased residual deformation and unsatisfactory metal structure the relation is the higher the greater is the degree of the metal softening.

Rossmanith H. P., Loibnegger F., and Huber R. Thermo-mechanical fatigue fracture due to repeated braking of railway wheels
Marahleh G., Kheder А. R. І., and Hamad H. F. Creep life prediction of service exposed turbine blades
Timofeiev B. T. Static and fatigue crack growth resistance of 22К steels

SUMMARY. Data on fatigue and static crack growth resistance of 22К steel, used for pipelines of a large diameter of NPP with BWR-1000 reactors are generalized. Data on fatigue crack propagation at 20 and 350°C and R = 0.1–0.7, and also fracture toughness results are presented.

Gnyp I. P., Neprila M. V., and Hanulych B. K. Creation of heat- and impact-resistant coatings of main pipelines

SUMMARY. Lamellar composite heat-resistant silicon organic sandwich-type coatings with thin polyurethane silicon organic interlayers have been developed. As binding components the following lacquers were used: for primer – silicon organic lacquer KO 921 with addition of epoxy resin ЭД-20; for thin soft interlayers – silicon organic lacquer KO 921 with addition of elastomer PZ 1040P; for thick hard layers – silicon organic lacquer KO 921 only. Mineral filler consisted of the mixture of coal ash and omniocarb in the proportions of 70 to 30 mass.%. Laboratory specimens containing two hard layers and two interlayer; three hard layers and two thin interlayers were manufactured and tested. Investigations showed that the developed lamellar composite coatings by their characteristics exceed the requirements of the State Standard of Ukraine on the corrosion protection of steel main pipelines. They possess high impact strength, improved elasticity and by their electric insulation characteristics exceed there requirements by an order of magnitude. The complexity of the technology of lamellar composite coatings application was noticed and the necessity of its improvement was stated out.

Uchanin V. M. Eddy current flaw detection of elements of constructions

SUMMARY. The perspective ways of development of eddy current method of structural elements testing are presented. The possibility of subsurface flaw detection based on low operational frequency application and quantitative testing with detected flaw identification and estimation are shown. The possibility of application of high operational frequency for product thin surface layers and low-conductive material testing is shown. The possibilities of new eddy current transducers and flaw detectors, and also new testing technologies developed as a result of their application are presented. New methods of information processing such as method of two- dimensional visualization of testing results are presented.

Pokhmurskyi V. I., Khoma M. S., Dzhala R. M., Arkhipov O. H., and Chuchman M. R. Evaluation of the sensitivity of the polarization current method to structural elements damages

SUMMARY. The opportunity of application of polarizing current method for corrosion monitoring of the working equipment is shown. The proposed calculations demonstrate show, that the given technique allows to estimate the equipment damage rate at a distance from an electrochemical probe not less than 5 m. Sensitivity of the method depends on the electrolyte resistance and sizes of the tested object.

Pohreliuk I. M., Fedirko V. M., Yaskiv O. I., Tykhonovych V. V., and Proskurniak R. V. Improvement of corrosion-resistance by carbonizing and nitriding of titanium Ti–Al–Mo–V alloy

SUMMARY. Regularities of coatings formation on Ti–Al–Mo–V alloy during saturation from carbon-nitrogen-containing medium (oxygen amount not higher than 0.01...0.0005 vol.%) and its corrosion-electrochemical behaviour in 80% sulphate acid aqueous solution were investigated. The features of phase formation at various saturation temperatures were shown. For instance, at temperatures below 1100oC the nitrides compounds, and at temperatures above 1100C – carbonitrides are formed. It was shown that physical and mechanical characteristics of nitride coatings, which are formed in carbon-nitrogen-containing medium, are improved as compared to nitriding. The increase of TiN amount in nitrided layer due to saturation from carbon-nitrogen-containing medium improves the surface corrosion characteristics. In spite of high roughness, the protective properties of carbonitrides remain very high.

Mikulich V., Blochwitz C., Skrotzki W., and Tirschler W. Influence of texture on the short fatigue crack growth in austenitic stainless steel
Paustovskyi O. V., Rud’ B. M., Sheludko V. Ye., Kremenytskyi V. V., Telnykov Ye. Ya., Honchar A. H., Bloshchanevych O. M., and Zakharchenko I. V. Strain sensitivity of resistive thick films, based on BaB6 and SnO2–Sb after laser radiatio

SUMMARY. The influence of laser radiation on strain-sensitivity of ВаВ6 and (SnO2–Sb)-based thick films is investigated. The character of electrical resistance change depending on laser pulse duration is studied. Laser processing of (SnO2–Sb)-based thick films with a nanosecond duration pulse is shown to increase a strain sensitivity factor by 40%.

Kozinov S. V., Loboda V. V., and Kharun I. V. Periodic system of interphase cracks with contact zones in isotropic bimetal under tension and shear

SUMMARY. A closed form solution to the plane problem of the theory of elasticity for an infinite isotropic bimaterial plane (space) with a periodic set of interface cracks in the presence of the frictionless contact zones near the crack tips is obtained by means of the complex function theory methods. As a result of the numerical analysis of the obtained solution the interaction of the cracks is investigated, i.e. the variation of contact zone lengths and SIFs with respect to the distance between the cracks is determined.

Mykhas’kiv V. V. and Butrak I. O. Dynamic stresses in the vicinity of a crack along cylindrical surface

SUMMARY. By the boundary integral equation method in combination with the small parameter method a problem on low frequency loading of a shallow crack along cylindrical surface in an infinite elastic solid is solved. The crack front distributions of modes I–III SIFs are obtained for different crack curvatures and wave numbers.

Martyniak R. M., Malanchuk N. I., and Monastyrskyi B. Ye. Shear of interpressed semiplanes with a surface groove. P. 2. Non-complete contact Fatigue life under variable-amplitude loading according to the cycle counting and spectral methods using the Serensen–Kogayev hypothesis

SUMMARY. The elastic contact problem for two half–planes, one of which contains a surface groove, has been considered. The intercontact gap appearing under consecutive loading by normal and tangential forces is taken into account. By using the Kolosov–Myskhelishvili complex potentials the problem is reduced to a sequence of singular integral equations, first of them been solved analytically, the second one – numerically. The numerical procedure implies separation of the root singularity and presentation of the regular part by Chebyshev polynomials of the first kind with unknown coefficients, which are determined by using the collocation method. The dependence of the gap’s length and slip zone size on load at infinity; distribution of tangential and normal stresses at the contact surface are analyzed.

Borysenko V. A., Arkhipov O. H., and Linko H. V. Failure of parts of pirolyses gas compression turbines
Shvets V. A., Lavrenko V. O., and Talash V. M. An experience of application of Al–Zn–Ca alloy protectors
Bahliuk H. A. A calculation model of relation of hardness and strength of porous materials
Buketov A. V. Improvement of the accuracy of evaluation of dynamic characteristics of epoxy composites

Revised: 06.09.2006