Danilov

pp. 43-52

pp. 35-43

pp. 361-371

pp. 384-396

pp. 771-779

This article presents the basic theory of helical spring, gives the stress formulas of each component in the cross section of spring, compares the analytical study with the simulation results, which are created using ABAQUS program. The research description presents a distribution and character of stress contour lines in the cross section of spring under the instantaneous load, explicates the relaxation law with time. The paper studies a relaxation phenomenon of stress. A finite element model for stress analysis is created to analyze the stress distribution of creep at high temperature. The article analyzes the change law of creep stress with time under constant load and at a fixed value of compression.

Development of a method for calculating relaxation of a contact between a fuel element and a spacer grid cell is a necessary condition for solving complex deformation problems of fuel assembly under intensive temperature and neutron fields. Due to relaxation of contact interaction the fuel element can slide in the spacer grid cell; this results in decreasing stiffness of overall assembly and its deformation. A method for calculating relaxation of contact interaction between a fuel element and a spacer grid cell based on the finite element method and the Schwarz alternating method was proposed in this work. Calculation of relaxation with the use of the proposed method will allow to estimate operation time of a fuel element till its sliding, and also to determine the disability criterion of fuel assembly.

The authors formulate a mathematical model for relaxation resistance of a spring working under the conditions of neutron irradiation and high temperature; a method of its analysis was developed. The model and the analysis method are based on the fundamental equations of the creep theory constructed with the use of the finite-difference algorithm. This model is capable of creep and relaxation analysis of a spring based on various initial spring loads and geometrical parameters. Comparison of results of the proposed model with the well-established industrial analysis computer program “Ansys 12” is included in the article.

The method of stabilization of the trunk pump unit (TPU) was presented in this article. Since TPU increased oil pressure during its transportation through the pump, the heavy shear force arose. This force was applied to pipes, which had been jointed to the pump, and to unit frame. To reduce the influence of negative shear force it was offered to compensate this force with system of hydrocylinders

The mathematical model of hydraulic accumulator performance was described in this article. The mathematical model was based on equations of the ideal gas law and the soft shells theory. Developed model allowed to analyze various hydraulic accumulator operating regimes numerically. The aim of this article was to compare the obtained results with the experimental data, i.e. to understand whether the created model was correct.