Papers by Keyword: Elastic-Plastic Deformation

Abstract: Straightforward and reverse descriptions are used to describe the metal’s plasticity zone. For the straightforward descriptions of the hardening zone, the “reference” point is the relative deformation ε_y corresponding to the yield strength σ_y. The deviation of the relative deformations in the metal hardening zone is measured relative to ε_y, and the deviation of the normal stresses is measured relative to σ_y. For the reverse descriptions of the metal hardening zone, the “reference” point is the relative deformation ε_u corresponding to the ultimate strength σ_u. The deviation of the relative deformations in the metal hardening zone is measured relative to ε_u, and the deviation of the normal stresses is measured relative to σ_u.

Abstract: During the experimental study, a pronounced beating and sealing of the side surface of the tubular, cylindrical blanks was recorded. It is established that cracks appear and develop in the central part of the lateral surface, i.e., it are destroyed. This fact confirms the claim that the destruction of tubular, cylindrical blanks of some materials begins on the side surface. It is established that the bases of analytical dependencies between the components of deformations describe the obtained results of the experimental study of SR tubular, cylindrical blanks within the error of the experimental data, which made it possible to construct a number of mathematical models for the purpose of further study of the SDS and the method of their determination.

Abstract: This article analyses the process of occurrence of the surface roughness during the ultrasonic hobbing of the fine pitch gears from the viewpoint of the theory of elastic-plastic contact, and suggests analytical solutions and regression equations to estimate the roughness parameter Ra in both conventional and ultrasonic machining.

Abstract: This paper deals with the problem of stresses in the surface layer of materials after machining. It analyzes residual stresses as one of the factors affecting the state of the surface layer after machining. It describes the methods for measuring residual stresses and evaluates them from the point of view of suitability for industrial practice. A new method of measuring residual stresses in the surface layer of a workpiece for laboratory use has been proposed and experimentally tested. At the end of the article the options for further solutions in this area are proposed.

Abstract: The paper considers the issue of shrinkage stresses of elastic-plastic deformation in the casting ‘Slag bowl’ resulting in a discontinuity and hot crack formation. The stress-strain state of the wall of the as-cast billet during the process of power interaction between the casting and the mould has been analysed according to the existing algorithms. Quantitative indicators of the components of the total stress state in the wall of the casting at the time of hot crack formation were determined. It was found that the bending stress greatly affects the defect, comprising 96 % of the tensile strength of the casting material at the time of destruction. The techniques aimed at reducing hot crack formation in a body of as-cast billet based on the results from the calculations are recommended. In accordance with the proposed recommendations, the changes in the technological parameters in production of a batch of pilot castings showed a decrease in the defect on hot cracks by 73 %.

Abstract: In the present study contact between elastic-plastic dissimilar spherical particles are investigated. The investigation is based on analytical and numerical methods and in the latter case in particular the finite element method. The results presented are pertinent to force-displacement relations at contact when elastic and plastic deformations are of equal magnitude. Especially, hard metal particles are considered with a typical application area being analysis of powder compaction.

Abstract: This article deals with the reasons for gear failure - Flank breakage on tooth of spur gears with helical and straight involute gears. Gear flank breakage can be observed on edge zone-hardened gears. The creation of flank and tooth breakage and FEM simulation of flank breakage on tooth are described in this article. In the article are also described and short photo documentation from real load tests on mechanically closed stand for testing of gearing with helical gears and different nitrided depth.

Abstract: Arrangement of Internal Stresses in Deformed Austenitic Steel is Studied. the Internal Stresses are Determined Using Parameters of Bending Extinction Contours Observing on Electron Microscope Images of the Steel. at the Deformation Degree ε = 14% the Average Internal Stress Values inside Separate Grains with Complex Bending is much Greater than <σ> in a Grain with Simple Bending. the Difference of <σ> at the Deformation Degree ε = 25% in Grains with Simple and Complex Bending is Small. this is Explained by Considerable Relaxation of the Internal Stresses in the Deformed Steel Caused by Appearance at ε > 20% of a Great Number of Microtwin Packages

Abstract: Arrangement of internal stresses in deformed austenitic steel is studied. The internal stresses are determined using parameters of bending extinction contours observing on electron microscope images of steel.

Abstract: The excess density of dislocations and internal stresses in local places of all polycrystal grain are determined. In work the methods of bending extinction contours observed by TEM is used to determine internal stresses of the deformed material. Thus depending on the deformation nature in each case components of elastic and plastic deformations or only plastic deformation was considered. The paper discusses the results of distribution of excess dislocation density and internal stresses within the grains of the austenitic steel deformed by tension (ε = 25%).