Modeling of Material Deformation Kinetics in the Prefracture Zone

Based on the concept of complete stress–strain diagrams, we propose a new model describing the law of stress distribution in the prefracture zone in plastic materials in view of the type of the stressed state.     

The Delin software system and examples of using it in constructing systems for control of thermal power installations

The possibilities of using the Delin software system as a fully functional product intended for designing and implementing algorithms for monitoring and control of power installations are considered. The main components of the software system are described. Data on a few types of systems constructed on the basis of the Delin software system and put in operation at power stations and other facilities are presented.     

Calculation of the Filtration Coefficient and the Flow Resistance of a Fibrous Filtration Membrane in Terms of the Hausdorff–Besicovich Dimension

The filtration coefficient and the flow resistance are calculated for filtration membranes made from fibers whose length and diameter constitute an infinitely decreasing geometric progression. These parameters can be described in terms of the Hausdorff–Besicovich dimension and are optimum when the membrane has a fractal structure.     

Effect of stressed-state form on failure kinetics and crack resistance in martensitic-aging steel. 1. Study of the failure process stages

We investigate the kinetics of failure in martensitic-aging steel during the concluding stages of deformation in statically elongated smooth specimens and in specimens with stress concentrators. Particular attention is devoted to the unique features encountered in the formation and onset of a separating macrocrack in the specimens being tested. Initially, using the methods of detailed metallography, we reproduce the pattern of prefailure zone formation, the crack trajectories subsequently passing through these zones. We have noted common and distinguishing features in damage formation in the steel being tested, with consideration given to the form of the stressed state.Translated from Problemy Prochnosti, No. 8, pp. 3–13, August, 1991.     

Effect of the grain size on the accumulation of damage in a metal subjected to plastic deformation

The integrated assessment of the accumulation of damage in D16 aluminum alloy with coarse grains (≈3 and 8 mm) grown by a special thermal treatment shows that the grain size can strongly affect the rate of accumulation of damage in metallic materials under static loading. The degree of damage to the metal correlates well with some parameters of its damping ability and acoustic emission. These results are important from the scientific point of view and can be used for the solution of practical problems, in particular, for the improvement of existing methods and developing new methods and equipment for nondestructive testing of deformed metals. Translated from Problemy Prochnosti, No. 5, pp. 5–13, September–October, 1997.     

Model of damage cumulation in metallic materials under static tension

The article deals with a new phenomenological model of damage cumulation in metallic materials subjected to static tension. The main parameter of the running state of the material, which is put in correspondence with the degree of loosening, is the Poisson ratio at the stage of loss of strength (the descending part of the stress-strain curve). The suggested model describes satisfactorily the results of specially arranged experiments.Translated from Problemy Prochnosti, No. 7, pp. 31–40, July, 1995.