Vol 8, No 2-4 (2014)
- Year: 2014
- Articles: 13
- URL: https://journals.eco-vector.com/2074-0530/issue/view/3736
Articles
Problem of long-term high temperature strength of metal materials
Abstract
The concept of brittle and ductile-brittle fracture under high-temperature Kachanov-Rabotnov creep laid the foundations of continuum damage mechanics. The article specifies the parameter of damage and formulates a system of interconnected consistent kinetic equations of the creep rate and damage. According to the obtained solutions, theoretical curves of the change in density, creep and long-term strength are constructed.
Izvestiya MGTU MAMI. 2014;8(2-4):5-14
5-14
15-17
18-22
Integration of Navier-Stokes equations
Abstract
The author considers the integration of the motion equations of a Newtonian fluid (Navier-Stokes equations) in vector form, taking into consideration a separation of vector Navier-Stokes equation on the two equations containing separately linear and quadratic terms. On this basis, the paper demonstrates the possibility of integration of separated motion equations of an incompressible viscous fluid, which is determined in a greater extent by the characteristics of flow: boundary conditions, axisymmetric, nonaxisymmetric flow and others.
Izvestiya MGTU MAMI. 2014;8(2-4):23-31
23-31
Influence of gradient tensor shape in geometrically nonlinear endochronic theory of creep
Abstract
The authors consider the tensor-parametric version of endochronic theory of inelasticity for large deformations and rotations, taking into account temporal effects. The paper examines the influence of a parameter presented in the deformation gradient, and hardening parameter on the shape and magnitude of the curve "creep~time." The corresponding examples are given in the article
Izvestiya MGTU MAMI. 2014;8(2-4):32-35
32-35
Climb in analytical calculation of spatial truss
Abstract
For spatial truss with triangular section and small camber, the analytical solution for the deflection is found. This allowed to find a proper camber at which the farm is rectified under the load. A simple asymptotic solution is given. Basis for the solution was the method of induction by means of Maple computer mathematics.
Izvestiya MGTU MAMI. 2014;8(2-4):36-39
36-39
Model of effective dynamic viscosity of two-phase mixtures
Abstract
The paper proposes a method of calculating the effective viscosity of the two-phase mixture that takes into account the particle size distribution, liquid tightness in the interparticle space and the influence of particle shape. The method explains an existing scatter of experimental data.
Izvestiya MGTU MAMI. 2014;8(2-4):40-46
40-46
Comparative analysis of standardized and finite-element approaches to strength calculations on example of assembly table
Abstract
On the example of the strength static calculation of assembly table, there is made a comparative analysis of the accuracy and labour-output ratio of the standardized approach, regulated by OST 92-8767-76, and the finite element calculation in FEMAP using NASTRAN linear solver. The author gives the estimation of labour-output ratio and the relative error of determining the location and magnitude of maximum stress in the structure. It is shown that the finite element calculation must be included in industry standards.
Izvestiya MGTU MAMI. 2014;8(2-4):47-51
47-51
Solution of bifurcation problem for cylindrical shell under complex loading
Abstract
The paper considers the bifurcation problem of a circular thin-walled cylindrical shell in view of complex strain at the moment of loss of stability under proportional subcritical loading by axial compressing force, torque and internal stress in the deviatoric A.A. Ilyushin's strain space. A relation between stresses and strains is taken in accordance with determining relationships of the hypothesis of coplanarity. For determinative functions of plasticity few variants of approximation, which were offered by V.G. Zubchaninov, are used.
Izvestiya MGTU MAMI. 2014;8(2-4):52-56
52-56
57-60
Stability of three-layer cylindrical shell of composite material with orthotropic intermediate layer
Abstract
The article deals with the stability of a three-layer cylindrical shell under external hydrostatic pressure. The intermediate layer (filler) is considered as a three-dimensional orthotropic body. The proposed algorithm for calculation of the upper critical pressure is tested on well-known solutions of the stability of three-layer cylindrical shells.
Izvestiya MGTU MAMI. 2014;8(2-4):61-67
61-67
Linear minimax filtering of scalar random process at presence of fuzzy disturbance with limited variance in net component of observation
Abstract
In this paper the author investigates the problem of scalar minimax filtering in the presence of an unknown fuzzy disturbance in a stationary process with a known spectral density. It is known only moment restrictions about spectral density of the disturbance. The disturbance satisfies the restrictions with specified subset of possible concentration of the positive measure frequency axis (possibly infinite). Interference measurement is assumed to be given as a white noise of known intensity. Illustrative examples are given.
Izvestiya MGTU MAMI. 2014;8(2-4):68-73
68-73
Response of stationary gas turbine unit with rotor in plain bearings to seismic impact
Abstract
The authors investigated the response to an earthquake of magnitude up to 9 points for the two schemes of stationary gas turbine unit (GTU): with a heavy rotor in full plain bearings and a flexible rotor in journal bearings with self-aligning pads, and shoe-type bearings. The orbits of the rotor and the deformation of body parts in stationary and during the seismic impact are determined, that allowed to estimate the change of clearances in the gas-dynamic channel and bearings, and make a conclusion for GTU on capacity for work under seismic impacts.
Izvestiya MGTU MAMI. 2014;8(2-4):74-85
74-85