scholarly journals Calculation of the stress-strain state in a shaft lining during thawing of the frozen wall

2021 ◽  
Vol 32 ◽  
pp. 71-78
Author(s):  
M. Zhelnin ◽  
A. Kostina ◽  
E. Esina ◽  
O. Plekhov
2019 ◽  
Vol 240 (6) ◽  
pp. 628-637
Author(s):  
Maksim A. Karasev ◽  
◽  
Maria A. Buslova ◽  
Maria A. Vilner ◽  
Tai Tien Nguyen ◽  
...  

Author(s):  
O. L. TIUTKIN ◽  
V. А. MIROSHNYK ◽  
I. V. HELETIUK

Purpose. The construction of the Dnipro Metro, which today is characterized by high efficiency and widespread introduction of new technologies, has proved the need for predesign, design and construction work. The purpose of the scientific article is to identify during the complex analysis of the structure of the mine shaft its stress-strain state, which was obtained during the numerical analysis and geodetic monitoring. Methodology. During the complex analysis of the shaft № 16-bis of the Dnipro Metro, prognostic calculations of the stress-strain state were performed. To do this, a finite-element model is built, in which fully reflects the geometric features of the shaft, the load on it and boundary conditions. Part of the comprehensive analysis is geodetic monitoring, which is carried out during the construction of the shaft and during its operation. The works included the measurement of deformations both in the lining of the shafts and in the sections of the mine workings, as well as on the surface near the houses along the route in the area of influence of the working workings. Findings. During the numerical analysis of the structure of the shaft № 16-bis of the Dnipro Metro, displacement and force factors (normal forces and bending moments) were determined. Based on these results, the reinforcement of the elements of the shaft lining (bored pile, cap beam, reinforced concrete ring beam) was selected. The value of the deformed state obtained from the prognostic analysis indicates on the insignificant displacements of the designed structure. During the geodetic monitoring, horizontal and vertical deformations of the № 16-bis shaft lining were recorded, which were caused by the influence of public transport and heavy vehicles. But the values of these deformations reached 1 … 2 mm, which for their effect on buildings and structures is within normal limits. Originality. A comparison of the deformed state obtained during numerical analysis and geodetic monitoring, which proved the high accuracy of the prognostic calculation. Practical value. The results of a comprehensive analysis of the mine shaft of the Dnipro Metro made it possible to carry out a test the design solution and ensure high strength and stability of the lining made of bored piles.


2021 ◽  
Vol 32 ◽  
pp. 101-108
Author(s):  
A. Kostina ◽  
M. Zhelnin ◽  
O. Plekhov ◽  
L. Levin

2019 ◽  
Vol 240 (6) ◽  
pp. 628-637 ◽  
Author(s):  
M. A. Karasev ◽  
◽  
M. A. Buslova ◽  
M. A. Vilner ◽  
T. T. Nguyen ◽  
...  

Author(s):  
А. Г. Гребеников ◽  
И. В. Малков ◽  
В. А. Урбанович ◽  
Н. И. Москаленко ◽  
Д. С. Колодийчик

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.


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