scholarly journals Stress-strain state analysis and optimization of rod system under periodic pulse load

2018 ◽  
Vol 143 ◽  
pp. 01003
Author(s):  
Grigory Grebenyuk ◽  
Maxim Veshkin ◽  
Vladislav Maksak ◽  
Olga Nosireva
Keyword(s):  
Strain State ◽  
Pulse Load ◽  
Stress Strain ◽  
Stress Strain State ◽  
Periodic Pulse ◽  
Rod System ◽  
State Analysis

scholarly journals Stress-strain state analysis and optimization of rod system under periodic pulse load

2018 ◽  
Vol 143 ◽  
pp. 01003
Author(s):  
Grigory Grebenyuk ◽  
Maxim Veshkin ◽  
Vladislav Maksak ◽  
Olga Nosireva
Keyword(s):  
Strain State ◽  
Equations Of State ◽  
Traditional Approach ◽  
Pulse Load ◽  
Stress Strain ◽  
Stress Strain State ◽  
Periodic Pulse ◽  
Rod System ◽  
Nonlinear Mathematical Programming ◽  
Homogeneous Matrix

The paper considers the problem of analysis and optimization of rod systems subjected to combined static and periodic pulse load. As a result of the study the analysis method was developed based on traditional approach to solving homogeneous matrix equations of state and a special algorithm for developing a particular solution. The influence of pulse parameters variations on stress-strain state of a rod system was analyzed. Algorithms for rod systems optimization were developed basing on strength recalculation and statement and solution of optimization problem as a problem of nonlinear mathematical programming. Recommendations are developed for efficient organization of process for optimization of rod systems under static and periodic pulse load.

scholarly journals A Calculation Procedure for Strength Analysis of Wave Guides for Ensuring Improved Mass-Dimensional Parameters

2020 ◽  
pp. 50-61
Author(s):  
I.V. Kudryavtsev ◽  
M.M. Mikhnev ◽  
P.N. Silchenko
Keyword(s):  
Wall Thickness ◽  
Distribution Systems ◽  
Strain State ◽  
Stress Strain ◽  
Second Stage ◽  
Stress Strain State ◽  
Rod System ◽  
Local Areas ◽  
Dimensional Parameters ◽  
Strength And Stiffness

This paper presents a calculation procedure for designing waveguides with iproved mass-dimensional parameters, which ensures the required strength and stiffness characteristics under static, dynamic and deformational loads. The procedure is based on the analysis of methods for determining the stress-strain state of the waveguide-and-distribution systems of spacecraft. The first stage of the procedure involves modelling the waveguide-and-distribution systems in a general formulation by a rod structure with equivalent loading and fixing conditions and determining the stress-strain state of such a system. At the second stage, local areas with the maximum stress-strain state values are selected for a further refined analysis in the rod system. An evaluation of the influence of the waveguide wall thickness on the general stress-strain state is performed. It is shown that when the waveguide wall thickness varies in the range of 0.25 – 2.50 mm, the strength and stiffness of its sections under static loads basically follow the linear law. It is established that under dynamic loading the wall thickness has almost no effect on the resultant stress-strain state of the waveguide arising under the influence of forced fluctuations and quasi-static loading owing to its dependence on the ratios of mass, moments of inertia and resistance, which for some standard sizes of the waveguides will be almost constant. The equations obtained for the rod system cannot be used for evaluating the influence of the wall thickness on local stress-strain state in the form of wall deflection, local loss of stability, etc. In view of this, at the second stage of modelling local areas of interest are selected and transformed into 3D thin-walled structures, with translation into finite element method programs for a more exact analysis. In the future, the proposed technique can be used to solve connected problems of interrelation and the influence of cross-sectional deformations in local zones of the waveguide on the changes in electromagnetic fields with the formation of parasite waves. This will significantly improve the quality of radio engineering characteristics of the waveguide and distribution systems while ensuring their strength, stiffness and minimal mass-dimensional parameters.

scholarly journals Stress-strain state of a three-layer cylindrical shell under internal axisymmetric pulse load

2020 ◽  
pp. 145-151
Author(s):  
Viktor Gaidaichuk ◽  
Kostiantyn Kotenko
Keyword(s):  
Finite Element ◽  
Cylindrical Shell ◽  
Strain State ◽  
Layer Structure ◽  
Three Dimensional ◽  
Pulse Load ◽  
Geometrical Parameters ◽  
Time Interval ◽  
Stress Strain ◽  
Stress Strain State

The problem of dynamic deformation of a three-layer cylindrical shell under non-stationary loads in the case of rigid clamping of the shell ends is considered. The article presents the results of assessing the stress-strain state of a three-layer cylindrical shell, taking into account its structural feature, the ratio of the sheathing thickness and the physical and mechanical characteristics of a one-piece polymer filler. Calculations were performed by software complex Nastran. The values of displacements and stresses were calculated by the algorithm of direct transient dynamic process. The step duration of the time interval was 0.0000025 s, and the total number of steps was 200. The choice of the type of three-dimensional finite element was due to obtaining more detailed and accurate calculation results. The finite element model included 19000 three-dimensional finite elements and numbered 20800 nodes. The influence of geometrical parameters of shell layers with different physical and mechanical properties of one-piece filler on the stress-strain state under axisymmetric internal impulse load is investigated. Numerical results on the dynamics of the three-layer structure, obtained by the finite element method, allow to characterize the stress-strain state of the three-layer elastic structure of the cylindrical type at any time in the studied time interval. Optimization of the shell design is recommended. Changing the ratio of the thickness of the internal and external shells of the shell significantly affects the stress-strain state of the shell and its performance. Increasing the thickness of the internal layer of the shell significantly contributes to the increase of the latter. Comparison of the given results with materials of other similar researches and positions, testify to objectivity of the made approach.

THE INVESTIGATION OF DYNAMIC EFFECTS UNDER MICROSCALE PULSE LOAD

2021 ◽  
Vol 4 ◽  
pp. 61-68
Author(s):  
Nina Yakovenko ◽  
◽  
Andrey Bondarchuk ◽  
Oksana Kovalchuk ◽  
◽  
...  
Keyword(s):  
Phase Composition ◽  
Strain State ◽  
Equations Of Motion ◽  
Iteration Process ◽  
Pulse Load ◽  
System Of Nonlinear Equations ◽  
Time Step ◽  
Stress Strain ◽  
Stress Strain State ◽  
Inelastic Material

Axisymmetric problem of heat pulse irradiation of a cylindrical solid is considered. Nonlinear behavior of the material is described by the generalized Bodner-Partom model of flow. The nature of generalization lies in applying the rule of mixtures for the determination of parameters of the model responsible for yield point and ultimate strength. The considered model enables one to estimate the residual stress-strain state more exactly. During subsequent in-service loading of cylindrical solids, this state strongly affects the fatigue resistance of elements. The problem is solved by the time step integration method, iterative method, and finite element method. In each time step, we realize a double iteration process. The first is connected with the integration of the system of nonlinear equations of flow, the second with the solution of equations of motion and heat conduction. The calculations are performed on a grid FEM, especially in the region of irradiation, for the correct modeling of thermomechanical behavior of the material. The grid parameters are chosen with the help of the criterion of practical convergence of the solutions. The investigation of the stress-strain state of an inelastic material with regard for the dependence of parameters of the flow model on the phase composition of a material is carried out by using of numerical simulation. The main result is the following: qualitative and quantitative effects of phase composition influence on inelastic characteristics are established, namely change of tensile residual stresses on compression. The results obtained in the work can be used in calculations of parameters of surface hardening technologies.

Applications of Multi-Level Method of Stress-Strain State Analysis in Ceramic Tools Design

2016 ◽  
Vol 827 ◽  
pp. 173-176 ◽  
Author(s):  
Valery V. Kuzin ◽  
Sergey N. Grigoriev ◽  
Mike Fedorov
Keyword(s):  
Strain State ◽  
Stress Strain ◽  
Ceramic Tools ◽  
Stress Strain State ◽  
Level Method ◽  
Multi Level ◽  
Groove Cutting ◽  
State Analysis

The multi-level method of stress-strain state analysis of ceramic parts is created. The algorithm for the designing of cutters with ceramic inserts is developed with the application of this method and it is successfully implemented in the manufacturing of cutter for groove cutting in tempered workpieces.

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