Analytical Calculation of Large-Scale Deflection of Pulse-Loaded Elliptic Plates

Large deflections of pulse-loaded elliptic and round plates made of hardenable elastoplastic materials are investigated analytically using an energy-based approach. Formulas that are convenient for engineering design have been derived.     

Penetration of a thick plate by a slightly deformable long rod

A numerical simulation has been performed for the high-velocity deep penetration of a slightly deformable long rod into a thick plate. The main features are examined for the multistage rod retardation, and a study is made on how the impact velocity affects the characteristic parameters. An analytical model is formulated for the interaction, which is convenient for engineering use. The calculation agrees well with available experiments.Translated from Problemy Prochnosti, No. 10, pp. 63—70, October, 1993.We are indebted to Professor Sh. U. Galiev for participating in the formulation and for fruitful discussions.     

Fracture of solids by radiation pulses as a method of ensuring safety in space

To determine the optimum conditions of fracturing or altering the trajectory of dangerous space objects (large iron or rock space bodies, threatening to collide with the Earth), and also destroy space debris in the space around the Earth, the author presents a mathematical formulation of the problem of calculating the dynamic strength of solids under the effect of high-energy loading pulses. The results of numerical modeling are compared with the experimental data for the formulation of cupola-shaped swollen areas on the rear surface of a metallic plate subjected to laser radiation. The change in the fracture mechanisms (front and rear spallation) with increasing energy of the effect has been detected. Recommendations are given for optimizing the pulsed laser effect on dangerous space objects to ensure the fragmentation or change their orbit.Expanded form of the document presented at the International Conference Space Protection of the Earth≓ (SPE'94, Snezhinsk, Russian, September 26–30, 1994).Translated from Problemy Prochnosti, No. 3, pp. 31–51, March, 1996.     

Dependence of the Depth of Penetration on the Parameters of an Elongated Striker

On the basis of numerical simulation of the process of penetration of impact-destructible elongated metallic strikers into impact-destructible thick plates, we study the influence of the geometric shape and material of the striker on the depth of penetration and the possibility of through penetration. The depth of penetration is analyzed for the case where the impact velocity approaches the hydrodynamic limit.     

Analytic evaluation of the stress-strain state of a pipeline elastically bent in the ground

We construct a mathematical model of three-dimensional bending with tension and torsion of a prestressed curvilinear pipeline in an elastic compliant soil with longitudinal and torsional frictiontype reactions. The model has the form of a system of 12 ordinary linear differential equations. It takes into account large initial displacements of the pipeline and the action of temperature and pressure linearly distributed along the axis of the pipe. The analytic solution of the problem obtained in elementary functions is of significant practical interest for the inspection and design-basis strength analyses of underground, surface, and above-ground pipelines. Scientific and Engineering Center of Materials-Science Support of the Production and Certification of Equipment of Nuclear Power Plants at the Institute for Problems of Strength of the National Academy of Sciences of Ukraine, Kiev, Ukraine. Translated from Problemy Prochnosti, No. 2, pp. 151 – 160, March – April, 1998.     

New technology for making patterns

Despite recent advances in computer modeling of the casting process, in many sectors it is necessary to make trial castings that must be checked before the beginning of serial production. Making such castings can be a bottleneck in the development of new products, and creating precision patterns as expeditiously as possible is one way to circumvent this difficulty. The British Research Center for Casting has developed several modern technologies to resolve these problems. Delkam—Ural. Translated from Metallurg, No. 4, pp. 40–41, April, 1997.     

Range of application of the acoustic approximation in high-speed collision

An analysis is made of high-speed collision under conditions of plane symmetry. A formula that is convenient for analysis is obtained to relate impact velocity and mass velocity in the body undergoing loading. The formula can be calculated with a high degree of accuracy within a wide range of collision velocities on the basis of the acoustic approximation for the collision of most pairs of materials. The range of application of the approximation for correct determination of pressure turns out to be considerably narrower.Translated from Problemy Prochnosti, No. 6, pp. 33–41, November–December, 1996.     

Numerical analysis of a three-dimensional branched pipeline using special software designed for estimation of the strength of the equipment of nuclear power plants

We describe the structure of an informational model of a branched three-dimensional pipeline, which is important for analysis of the stressed state of its elements, and formulate the basic principles of, its application. For rectilinear and (this is especially important) curvilinear segments of pipeline, we obtain relationships between the generalized displacements and generalized forces at every point of the considered segment. On the basis of these relationships, we formulate a procedure for application of the method of initial parameters to the analysis of the elastic state of the pipeline. This procedure is based on a simple single-stage sequence of passing through the entire pipeline to obtain a closed system of equations for the unknown generalized forces. In agreement with contemporary standards and documents, we develop an algorithm and realize an iteration procedure to take into account the effect of friction in the supports. Scientific and Engineering Center of Materials-Science Support of the Production and Certification of Equipment of Nuclear Power Plants at the Institute for Problems of Strength of the National Academy of Sciences of Ukraine, Kiev, Ukraine. Translated from Problemy Prochnosti, No. 2, pp. 87 – 100, March – April, 1998.