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Том 222, № 2 (2017)
- Год: 2017
- Статей: 8
- URL: https://ogarev-online.ru/1072-3374/issue/view/14817
Article
Determination of the Period of Subcritical Growth of Creep-Fatigue Cracks Under Block Loading
Аннотация
We formulate a mathematical model for the investigation of the processes of propagation of creepfatigue cracks in plates under block loading. The influence of the shape of loading blocks on the durability of structural elements is investigated and the the subcritical growth of creep-fatigue cracks in thin-walled structural elements is analyzed.
103-113
Arc Crack in a Homogeneous Electrostrictive Material
Аннотация
We consider the problem of determination of the stress-strain state of an elastic electrostrictive plane containing an arc crack and subjected to the action of electric and mechanical forces applied at infinity, which may be arbitrarily oriented relative to the crack axis. This problem is reduced to the problem of linear conjugation for a piecewise analytic function of complex variable. We obtain its exact analytic solution and deduce analytic expressions for the stresses at any point of the medium, crack opening displacements, and the stress intensity factors at the crack tips.
114-130
Interaction of Two Elastic Bodies in the Presence of Periodically Located Gaps Filled with a Real Gas
Аннотация
We model contact interaction of two elastic semiinfinite bodies in the presence of a real gas in the interface gaps formed by a periodic array of grooves on the surface of one of the bodies. The state of the gas is described by the van der Waals equation, which enables us to consider the phase transition from the gas into the liquid phase. The posed contact problem is reduced to a singular integral equation with Hilbert kernel for the height of the gap. This equation is transformed into a singular integral equation with Cauchy kernel and is solved analytically. To determine the length of the gap and gas pressure, we derive a system of transcendental equations from the condition of boundedness of the solution of this singular integral equation and from the van der Waals equation. The dependences of the gap length, gas pressure, contact approach, and contact compliance of the bodies on the applied load are analyzed.
131-142
A Crack in the Form of a Three-Link Broken Line Under The Action of Longitudinal Shear Waves
Аннотация
We solve the problem of determination of the dynamic stress intensity factors for a crack in the form of a three-link broken line. The crack is located in an infinite elastic medium with propagating harmonic longitudinal shear waves. The initial problem is reduced to a system of three singular integrodifferential equations with fixed singularities. A numerical method is proposed for the solution of this system with regard for the true asymptotics of the unknown functions.
143-154
Effect of Violation of the Continuity of Materials by Dispersed Microcracks on the Electroelastic Parameters of Piezoceramics
Аннотация
A continual model of deformation of piezoelectric materials weakened by a system of microcracks dispersed over the bulk of the material is constructed with use of the energy method. This method is based on the assumption of equivalence of the strain energy of the cracked electroelastic medium and the strain energy of a continuum modeling the indicated medium. A generalization of the Eshelby principle is used to determine the strain energy of microinhomogeneous media with inclusions.
155-166
Transient Thermal Stressed State in a Half Strip with Coating Caused by Heating of Its Lateral Surface
Аннотация
By using the Laguerre and Fourier integral transformations, we construct the solution of a plane quasistatic problem of thermoelasticity for a half strip with coating heated by a heat flow acting upon its ends and cooled through the surfaces of the coatings that are free of loads. The results of numerical analyses of the dependence of the thermal stressed state in a cermet on the rate of cooling and the relative thickness of the coating are presented.
167-180
Influence of the Lateral Process Zone Near the Tip of an Interface Crack on the Contact of its Faces
Аннотация
Under conditions of plane deformation, by using the Wiener–Hopf method, we compute a small-scale contact zone near the tip of an interface crack under the condition of formation of the lateral process zone in its vicinity. It is assumed that the dry friction of the faces according to the Coulomb law is realized in the contact zone. We determine the sizes of the contact zone and deduce an expression for the contact stresses and an equation for the determination of the index of singularity of stresses near the crack tip. The influence of the load, friction coefficient, and elastic characteristics of the joined materials on the sizes of the contact zone is investigated. It is shown that, in the presence of the process zone, the length of the contact zone begins to depend not only on the configuration of the external load but also on its value.
181-193
Quasistatic Problem of Thermoelasticity for a Cylindrical Shell with Heat Sources and Heat Exchange
Аннотация
We construct the solution of the quasistatic problem of thermoelasticity for a long cylindrical shell with axisymmetric distribution of heat sources in an annular region and heat transfer from the lateral surface according to the Newton law. The results are generalized to the cases of arbitrary number of heating rings. We study the thermoelastic states of the shell in the cases of one-ring and two-ring heating in the asymptotic mode.
194-204