The dynamic problem about elastic hollow cylinder with surfaces loaded arbitrary by forces depending on time is solved by a new method based on using finite differences with respect to time [12]. Numerical calculations of stress conentration, depending on time for cylinders of different width under impact loading have been done. Approbation of the method was realized for the problem about circular hole in an infinite body under impact loading over the whole surface.

A previously developed energy approach has been generalized for assessment of structural elements residual life time under biaxial loading. On this basis the mathematical model for determining the subcritical fatigue crack growth in a plate under biaxial cyclic loading has been formulated. Using this model the influence of biaxial cyclic loading parameters on the subcritical fatigue crack propagation period has been analyzed.

An review of SIF investigations for an edge shallow crack in an elastic half-plane under Hertzian load moving along its boundary has been done. Numerical data obtained by singular integral equations method have been compared with results of other authors. They agree best of all with the results of Keer and Bower, obtained by dislo-cation approach, and satisactorily with other data obtained by the finite element method.

The problem about the determination of the stress state at the circular rigid thin inclusion in the unbounded elastic matrix is solved. Harmonic oscillations in the matrix are the result of the action of the harmonic force on the centre of the inclusion. It is considered that one side of the inclusion is completely adhesive with the matrix, while the other side is exfoliated and conditions of the smooth contact are realized on it. The solution method is based on the presentation of displacements in the matrix by the discontinuous solution of Lame equations. Such a solution gives the opportunity to reduce the boundary problem to the system of singular integral equations concerning functions connected with jumps of displacements and stresses on the inclusion. This system is solved by the method of collocations with the use of special quadratic formulae for singular integrals. The obtained approximate solution allows us to investigate effectively the stress state in the matrix at the inclusion. At the given frequencies of the loading the stress concentration increases sharply.

The finite elements technique for modeling of material structural heterogeeity has been proposed. Material was examined as a composite of elasto-plastic matrix and brittle inclusions (dispersoids). Experimental data on inclusions density and its geometrical sizes have been taken into account. The proposed finite elements model describes unstable deformaion of Al–6%Mg alloy satisfactorily.

Using the results of investigations of the microstructure, mechanical characteisics and fracture micromechanisms of Ti–Si as-cast alloys it was shown, that compoiions with silicon content not exceeding 2 mass.% having satisfactory plasticity at room tempeaure, are perspective for the development of heat-resistant titanium alloys.

The approximate effective solution of the problem on the nonstationary stress concentration near a spherical crack located inside the tapered shaft under the influence of the impact tangential stresses on its face has been obtained. The approach based on the problem discretization by time with the help of the difference scheme is proposed. On the basis of the integral transforms method the problem is reduced to the integral equation relatively to the unknown displacement jump on the crack. This equation is solved by the orthogonal polynoial method. The formula for stress intensity factor calculation has been obtained.

The effect of the rarefaction of oxygen-containing medium in the range of 0.001...10 Ра on the formation of oxynitrides on the surface of c.p. titanium and its ПТ-7М, ОТ4, ВТ20, ВТ6c alloys during modification of nitrides formed at temperature 850?С by saturation in molecular nitrogen has been investigated. The formation of titanium oxynitrides becomes more intensive during increase of the rarefaction from 10 to 0.001 Pa. It is shown that surface microhardness increases after oxynitriding in comparison with nitriding, the depth of hardened layer is determined by isothermal exposure in nitrogen.

A concept of random field of diffusive type is introduced and its homogeneity is defined. Ergodic and quasiergodic fields are considered and necessary conditions are obtained for introduction of a physically small representative body element as well as conditions for interhange of averaging over an ensemble by averaging over a body volume. Statistically homogeeous random fields of diffusive type are considered. An effective radius of correlation is obtained. Spectral decompositions of random fields are written. It is shown that for a homogeeous random field spectral amplitudes are delta-correlated in density.

Analysis of the physicochemical reactions peculiarity leading to the passive metal surface fracture shows the impossibility of the adequate kinetic model construction. Foraliing of the system discreet states was proposed to be used for simulation of surface formation for pasive metals. The model of the electrochemical active surface transformation affected by pulse current polarization was constructed. The technological process scheme and a quantity criterion for finihing treatment were proposed.

Probabilistic methods of the fracture mechanics are applied to integrity assessment of cracked components subjected to static and cyclic loading. Various key issues related to a probabilistic analysis are discussed and accounted for in the calculations. An example illustrating the application of computational procedures to evaluate the integrity of a pipe with a spiral crack under static loading is presented. Finally, some available experimental results on fatigue crack growth in 15Х2МФА steel under cyclic bending are re-evaluated by statistical methods.

The procedure is proposed for evaluation of the process zone sizes under quasi-brittle fracture by transverse bending of the notched steel beam specimens.

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The difference of corrosion and electrochemical behaviour of the exploited low-carbon steel Ст3сп from different zones of the oil storage tank depending on its prior contact with operating environment of different aggressiveness in residual water from the oil storage tank of different refineries is found. A conclusion is drawn, that corrosion resistance of steel essentially decreased as a result of the long-term contact of steel with an aggressive service environment (residual or condensed water). It is established that oil-water emulsion interface is characterized by the highest corrosion activity and the oil-water emulsion – by the lowest one. It is shown, that the intensity of electrochemical processes on steel of those oil storage tank areas, which contacted during the service with residual or condensed water were higher than those which contacted with oil. It is established, that the least mineralized residual water with the least amount of chlorides were the least corrosion active.

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