scholarly journals The effect of distributed dislocations on bending of a rectangular beam with a preliminarily stressed layer under superposition of large strains

2019 ◽  
Vol 485 (6) ◽  
pp. 686-690
Author(s):  
V. A. Levin ◽  
L. M. Zubov ◽  
K. M. Zingerman

The formulation of problems on the equilibrium of a nonlinearly elastic solid with continuously distributed dislocations is proposed for the case of superposition of large strains. The numerical results showing the effect of distributed dislocations on the stress-strain state of the beam are presented.

2020 ◽  
pp. 32-44
Author(s):  
Liudmyla Skochko ◽  
Artem Shabaltun

The influence of the order of construction of houses on the formation of the stress-strain state of the system "foundation-foundation-above-ground structures" is investigated For this purpose, several options for setting tasks for the phased construction of multi-section building sections are considered. With this in mind, it should be noted that the construction of each subsequent section has an impact on the built entirely or partially adjacent section. That is why this effect should be investigated to predict how serious this impact may be, and to draw appropriate constructive decisions. Thus, the main objectives of the study are: Creation of SEM without taking into account the stages of construction of the house; Calculation of a house with a phased loading of 5 floors. Taking into account changes in the order of construction of sections; Formation of SEM taking into account the sequence of erection of sections without including the sequence of erection of floors within the boundaries of the current section; Research of the impact of the calculation of sections of a multi-section building without and taking into account the summary of subsequent sections. The research of the impact of the sequence of construction and installation of the object will allow us to assess the stress-strain scheme at all stages of construction, so changes in the behavior of the scheme will be recorded at all stages of construction specified by the designers. To do this, the change in the stress-strain state (VAT) of the system "foundation - foundations - above-ground structures" must be modeled with different options for stages of construction, taking into account the real parameters of the soil base and so on. The interaction of piles in different zones of sections, the work of grids in the foundations of high-rise buildings are considered. The research was carried out with the help of numerical modeling of the system "foundation - foundations - aboveground constructions". The redistribution of forces in the piles depending on the formulation of problems on the stages of construction of sections and design parameters (location of piles in characteristic zones, the influence of the stiffness of the aboveground part on the redistribution of forces). Characteristic zones in the foundation are distinguished: they are central, lateral, angular and especially at the joints of adjacent sections. The redistribution of efforts between piles and a grid is revealed.  


2021 ◽  
Vol 264 ◽  
pp. 02005
Author(s):  
Ibrakhim Mirzaev ◽  
Ruslan Kishanov ◽  
Nodirakhon Mansurova ◽  
Nematilla Nishonov ◽  
Mars Berdibaev

The article deals with the seismodynamics of underground pipelines of various configurations under spatial seismic influences. The stress-strain state of spatially located underground pipelines of complex orthogonal configuration at different angles of seismic load incidence was determined. Several problems were solved by analyzing numerical results of the seismodynamics of underground pipelines of complex orthogonal and non-orthogonal configurations.


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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