scholarly journals Mathematical modeling of transformable space structure dynamics

2019 ◽  
Vol 221 ◽  
pp. 01018 ◽  
Author(s):  
Vladimir Zimin ◽  
Alexey Krylov ◽  
Sergey Churilin ◽  
Zikun Zhang
Keyword(s):  
Strain State ◽  
Element Model ◽  
Space Structure ◽  
Space Structures ◽  
Elastic Rod ◽  
Stress Strain ◽  
Large Space ◽  
Structure Dynamics ◽  
Stress Strain State ◽  
Large Space Structure

Today large space structures are in focus of attention of engineers and designers of rocket and space equipment. In ground-based experiments, it is not always possible to carry out complex tests of large space structure functionality. Therefore, the development of mathematical models describing properly the transformable structure dynamics when they opened from the densely packed transport state to the operating position in the orbit becomes very important. To determine the stress-strain state of the frame elements when it is unfolding the shape of the framework is taken at the moments when relative velocities of the adjacent sections are maximal. Supposed, that at these moments the frame elements are getting on the stops limiting their relative angular displacements, and the structure behaves as an elastic rod with specified characteristics. Numerical analysis of the stress-strain state in the framework is carried out by means of a finite element model. Therefore, the represented mathematical model can be effectively used to predict the functional suitability of such transformable space structures already on the early stages of their development.

КОНСТРУКТИВНО-ТЕХНОЛОГІЧНІ ОСОБЛИВОСТІ ХВОСТО-ВИХ БАЛОК СІТЧАСТОГО ТИПУ З ПОЛІМЕРНИХ КОМПО-ЗИЦІЙНИХ МАТЕРІАЛІВ ВЕРТОЛЬОТІВ ТРАНСПОРТНОЇ КАТЕГОРІЇ

2020 ◽  
pp. 15-30
Author(s):  
А. Г. Гребеников ◽  
И. В. Малков ◽  
В. А. Урбанович ◽  
Н. И. Москаленко ◽  
Д. С. Колодийчик
Keyword(s):  
Finite Element ◽  
Strain State ◽  
Layer Structure ◽  
Metal Structure ◽  
Element Model ◽  
Stress Strain ◽  
Element Analysis ◽  
Mesh Structure ◽  
Stress Strain State ◽  
Mesh Structures

The analysis of the design and technological features of the tail boom (ТB) of a helicopter made of polymer composite materials (PCM) is carried out.Three structural and technological concepts are distinguished - semi-monocoque (reinforced metal structure), monocoque (three-layer structure) and mesh-type structure. The high weight and economic efficiency of mesh structures is shown, which allows them to be used in aerospace engineering. The physicomechanical characteristics of the network structures are estimated and their uniqueness is shown. The use of mesh structures can reduce the weight of the product by a factor of two or more.The stress-strain state (SSS) of the proposed tail boom design is determined. The analysis of methods for calculating the characteristics of the total SSS of conical mesh shells is carried out. The design of the tail boom is presented, the design diagram of the tail boom of the transport category rotorcraft is developed. A finite element model was created using the Siemens NX 7.5 system. The calculation of the stress-strain state (SSS) of the HC of the helicopter was carried out on the basis of the developed structural scheme using the Advanced Simulation module of the Siemens NX 7.5 system. The main zones of probable fatigue failure of tail booms are determined. Finite Element Analysis (FEA) provides a theoretical basis for design decisions.Shown is the effect of the type of technological process selected for the production of the tail boom on the strength of the HB structure. The stability of the characteristics of the PCM tail boom largely depends on the extent to which its design is suitable for the use of mechanized and automated production processes.A method for the manufacture of a helicopter tail boom from PCM by the automated winding method is proposed. A variant of computer modeling of the tail boom of a mesh structure made of PCM is shown.The automated winding technology can be recommended for implementation in the design of the composite tail boom of the Mi-2 and Mi-8 helicopters.

MODELING OF THE STRESS-STRAIN STATE OF A TRANSPORT TUNNEL UNDER LOAD AS A MEASURE TO REDUCE OPERATIONAL RISKS TO TRANSPORTATION FACILITIES

2020 ◽  
Vol 3 (8) ◽  
pp. 28-34
Author(s):  
N. V. IVANITSKAYA ◽  
◽  
A. K. BAYBULOV ◽  
M. V. SAFRONCHUK ◽  
◽  
...  
Keyword(s):  
Strain State ◽  
Moving Load ◽  
Element Model ◽  
Transport Infrastructure ◽  
Design Stage ◽  
Surface Load ◽  
Stress Strain ◽  
Stress Strain State ◽  
Operational Risks ◽  
Von Mises

In many countries economic policy has been paying increasing attention to the modernization and development of transport infrastructure as a measure of macroeconomic stimulation. Tunnels as an important component of transport infrastructure save a lot of logistical costs. It stimulates increasing freight and passenger traffic as well as the risks of the consequences of unforeseen overloads. The objective of the paper is to suggest the way to reduce operational risks of unforeseen moving load by modeling of the stress-strain state of a transport tunnel under growing load for different conditions and geophysical parameters. The article presents the results of a study of the stress-strain state (SSS) of a transport tunnel exposed to a mobile surface load. Numerical experiments carried out in the ANSYS software package made it possible to obtain diagrams showing the distribution of equivalent stresses (von Mises – stresses) according to the finite element model of the tunnel. The research results give grounds to assert that from external factors the stress state of the tunnel is mainly influenced by the distance to the moving load. The results obtained make it possible to predict in advance the parameters of the stress-strain state in the near-contour area of the tunnel and use the results in the subsequent design of underground facilities, as well as to increase their reliability and operational safety. This investigation gives an opportunity not only to reduce operational risks at the design stage, but to choose an optimal balance between investigation costs and benefits of safety usage period prolongation.

Empirical Formula Considering the Smoke Ventilation for Air Temperature in Large Space Structure under Fire

2011 ◽  
Vol 94-96 ◽  
pp. 587-593 ◽  
Author(s):  
Jin Liang ◽  
Su Duo Xue ◽  
Xiong Yan Li
Keyword(s):  
Air Temperature ◽  
Empirical Formula ◽  
Steel Structures ◽  
Space Structure ◽  
Space Structures ◽  
Large Space ◽  
Fire Temperature ◽  
Large Space Structure ◽  
Fire Smoke ◽  
Resistance Performance

Abstract.The fire smoke is one of the most important factors for the fire temperature field. Once the fire smoke has been exhausted effectively, the fire temperature will be reduced and the fire-resistance performance of steel structures may be improved as well. However, the research on the fire temperature in the space structures is almost bold, which could lead to the theoretical analysis result on fire temperature is quite different from the real condition. Accordingly, the air temperature condition on fire for large-space structures has been analyzed. Taken into account smoke ventilation, the empirical formula for air temperature in large space structure under fire has been modified.

scholarly journals On the issue of dynamic loading of supporting structures of special wheeled chassis

2019 ◽  
pp. 73-83
Author(s):  
V. I. Tarichko ◽  
P. I. Shalupina
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Dynamic Loading ◽  
Strain State ◽  
Element Model ◽  
Stress Strain ◽  
Full Size ◽  
Equivalent Stresses ◽  
Stress Strain State ◽  
Supporting Structures

The paper focuses on a method for assessing the dynamic loading of the frame of a special wheeled chassis when it moves on roads of various categories. Based on the developed finite element model of the frame, we obtained and analyzed full-size patterns of the stress-strain state of the frame and oscillograms of equivalent stresses in the most loaded zones of the frame.

scholarly journals An experimental study of the stress-strain state of the engine piston skirt on the engineless stand

2019 ◽  
Vol 20 (4) ◽  
pp. 285-292
Author(s):  
Sergei V. Smirnov ◽  
Vladimir V. Kopylov ◽  
Alexander R. Makarov ◽  
Alexander A. Vorobyev ◽  
Kirill V. Shkarin
Keyword(s):  
Finite Element ◽  
Strain State ◽  
Combustion Engine ◽  
Experimental Studies ◽  
Element Model ◽  
Design Development ◽  
Stress Strain ◽  
Piston Skirt ◽  
Stress Strain State ◽  
The Cost

The article describes the features developed by the authors of the profiling method of the piston skirt, provides the main parameters that affect the lubrication conditions of the piston skirt and the magnitude of mechanical losses. In computational studies, the basic formulas are given for determining the thickness of the oil layer in a piston skirt - cylinder sleeve conjunction to assess the nature of friction. To determine the deformations, the finite element method is used on the spatial model of the piston. To verify the finite element model, a stand for experimental studies was developed. The article describes the developed stand, the methodology and results of experimental studies of the stress-strain state of the two-piece piston skirt obtained at this stand and a comparative analysis of the results of the calculated and experimental studies of the stress-strain state of the two-piece piston skirt of a diesel engine. The research results showed that the developed stand can be used to verify mathematical models for calculating the stress-strain state of the piston skirt in the pilot production of internal combustion engine pistons to accelerate and reduce the cost of the piston design development process, as well as the results of experimental studies obtained at the stand, can be used as initial data for the developed mathematical model of the dynamics of the movement of the piston and the profiling of the piston skirt.

scholarly journals STRESS-STRAIN STATE OF FRAME STRUCTURES AT THE DIFFERENT SNOW PRESSURE

2019 ◽  
Vol 7 (2) ◽  
pp. 5-9
Author(s):  
Галина Кравченко ◽  
Galina Kravchenko ◽  
Елена Труфанова ◽  
Elena Trufanova ◽  
Денис Суслопаров ◽  
...  
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Strain State ◽  
Element Model ◽  
Frame Structures ◽  
Stress Strain ◽  
Snow Load ◽  
Stress Strain State ◽  
Snow Pressure ◽  
Snow Loading

The multi-variant loading of the large-span unique steel covering of the stadium under snow load is considered. The spatial finite element model is developed using LIRA software. The analysis of the existing schemes application of snow loading is carried out according to the codes. Four snow load cases on the stadium's covering are assumed for analysis. The analysis of the stress-strain state of the stadium structures, the selection and verification of sections of the steel covering are performed. The results show that it is necessary to simulate behaviour of a structure under all possible load cases.

Optimization Problems Arising from the Design of Pipes Made of Composite Materials

2020 ◽  
Vol 992 ◽  
pp. 1024-1029
Author(s):  
T. Bobyleva ◽  
A. Shamaev
Keyword(s):  
Strain State ◽  
Optimization Problems ◽  
Analytical Form ◽  
Radial Symmetry ◽  
Elastic Rod ◽  
Stress Strain ◽  
Stress Strain State ◽  
Fixed Weight ◽  
Applied Forces ◽  
Stiffness Characteristics

The work is devoted to the construction of analytical solutions for the stress-strain state of a cylindrical hollow elastic rod with a layered structure along the radius. Earlier, the problem of finding the stress-strain state of a rod of composite material fixed at one end with the applied forces and moments of forces at the other end was considered. An approximate representation of the solutions was given, which included auxiliary problems on one fragment of the cylinder, consisting of periodically repeating similar fragments. Such auxiliary problems in the general case do not have an analytical solution. In this paper it is shown that in the presence of radial symmetry of the rod section, it is possible to construct a stress-strain state in an analytical form. In addition, tensile and bending stiffness can be presented in an analytical form. The latter circumstance allows us to set a problem of optimizing the stiffness characteristics of a rod with its fixed weight. Optimization is carried out by varying the thickness of the layers of the same materials.

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