scholarly journals Determination of stress-strain state of reinforced slabs from non-linear material taking into account the influence of aggressive environment

2019 ◽  
Vol 27 (4) ◽  
pp. 488-503
Author(s):  
Alexandr Anatolyevich Treschev ◽  
Alexander Anatolyevich Bobryshev ◽  
Victor Grigoryevich Telichko ◽  
Lenar Nurgaleevich Shafigullin ◽  
Alexander Valeryevich Bashkatov

In this article, the construction of finite-elemental model of definition of stress-strain state of reinforced concrete plates in conditions of active deformation and simple loading in combination with long-term influence of chloride-containing operating environment. Non-linear behavior of concrete is simulated based on the determining relations proposed by Treschev, cracking and plastic deformations in armature are taken into account. The impact of the aggressive environment is taken into account in accordance with the model proposed by Petrov and Penina. In the article all basic correlations of finite elements method in convenient for software realization on a computer are given. As the object of research for this article is a concrete plate reinforced with steel reinforcement in a stretched area, which is under the joint influence of mechanical load and aggressive chloride-containing environment on the protective polymer–concrete layer. The load was taken evenly distributed across the entire slab area. At the solution of this problem the non-linear sensitivity of the basic material (concrete) to the type of the tense condition, plastic deformations in armature, degradation of a protective concrete at influence of external aggressive environment are taken into account. In the article some especially characteristic results of mathematical modeling of the specified model problem are given. The obtained results of joint influence on the plate of mechanical load and aggressive environment are analyzed.

Vestnik MGSU ◽  
2016 ◽  
pp. 28-38
Author(s):  
Ilshat Talgatovich Mirsayapov

The author offer transforming the diagram of ideal elastic-plastic deformations for the description of the stress-strain state of embedment of reinforcement behind a critical inclined crack at repeatedly repeating loadings. The endurance limit of the adhesion between concrete and reinforcement and its corresponding displacements in case of repeated loadings are accepted as the main indicators. This adhesion law is the most appropriate for the description of physical and mechanical phenomena in the contact zone in case of cyclic loading, because it simply and reliably describes the adhesion mechanism and the nature of the deformation, and greatly simplifies the endurance calculations compared to the standard adhesion law. On the basis of this diagram the author obtained the equations for the description of the distribution of pressures and displacements after cyclic loading with account for the development of deformations of cyclic creep of the concrete under the studs of reinforcement.


Author(s):  
A. V. Sedelnikov ◽  
S. V. Glushkov ◽  
V. V. Serdakova ◽  
M. A. Evtushenko ◽  
E. S. Khnyryova

The paper is devoted to simulating the impact of a thermal shock on a thin homogeneous plate in the ANSYS package. The assessment of the stress–strain state is carried out and the dynamics of changes in the temperature field of the plate is determined. The obtained results were compared with the data of other authors and can be used when taking into account the thermal shock of large elastic elements of spacecraft.


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.  


2019 ◽  
Vol 109 ◽  
pp. 00047
Author(s):  
Serhii Kurnosov ◽  
Volodymyr Zerkal

A method for calculating gas permeability of the rock massif depending on its stress-strain state is presented. By using methods of the mine experimental studies, influence of mining operations in the adjacent long walls on intensity of gas release from the previously worked-out long-pillar was determined, as well as impact of the massif stress-strain state on efficiency of the drainage boreholes. Formulas were obtained for calculating coefficients of the impact of zones with static and dynamic abutment pressure on intensity of gas draining in the previously worked-out long-pillar.


2018 ◽  
Vol 245 ◽  
pp. 03020 ◽  
Author(s):  
Svetlana Roshchina ◽  
Mikhail Lukin ◽  
Mikhail Lisyatnikov ◽  
Artem Koscheev

For the composite structures based on wood, that include reinforced wooden structures, allowance for the influence of wood specific features as a building material allows us to evaluate its structural design as accurately as possible and ensure the required reliability and durability. Creep that causes wood deformations evolving in time can be referred to the specific properties of wood to a greater extent affecting the operation of the reinforced wooden structures. Taking into account the state of the issue to determine the effect of the long-acting loads on the stress-strain state of the reinforced glued wooden structures, the article considers the application of the theory of elastic heredity as the most applicable to assess the deformability of wooden structures in time. The conducted experimental and theoretical investigations and the reinforced glued wooden structures observations during the operational process have shown that their stress-strain state changes significantly under the load over time. Glue compositions used to connect reinforcement with wood ensure their reliable joint operation, however, as the result of the wood creep where wood is the basic material, the redistribution of forces between the reinforcement and wood occurs there on and off. At the same time normal stresses in the reinforcement and the glue joint “reinforcement - wood” increase in the calculated cross sections while they decrease in the wood, which is caused by a change (decrease) in the wood elastic modulus. Allowance for the wood creep in the design of the reinforced wooden structures will allow to determine the stress - strain state of the structure in the design more precisely. Therefore, when developing the reinforced wooden structures design standards, this factor must be taken into account.


2014 ◽  
Vol 936 ◽  
pp. 1918-1924 ◽  
Author(s):  
Sergey Lezhnev ◽  
Eugeny Panin

In the development of new technology metal forming the main purpose is improvement the quality of the source material. The main aspect of quality improvement is increasing the strength characteristics. Often to increase the strength of deformable metal should be given reduced grain structure, up to subultra and even nanolevel. There are several ways to obtain sub-ultra-fine-grain structure of metals, and one of those ways is a method of severe plastic deformation (SPD), implemented in the whole volume of the deformable metal.In this work computer modeling was performed of the combined process "rolling-pressing" with the use of grooved rolls and equal channel step matrix with varying basic geometric and technological factors which have a significant impact on the process, what was made for the analysis of the impact of various factors on the stress-strain state of the process.


Author(s):  
Andrey Grabovskiy ◽  
Mykola M. Tkachuk ◽  
Anton Zavorotnii ◽  
Serhii Kutsenko S ◽  
Mariia Saverska ◽  
...  

Torsion shafts are the main elastic element of the suspension systems of a large number of vehicles. To simulate their reaction to the action of torque, the stress-strain state is analyzed taking into account the contact interaction with the spline sleeve. The features of the distribution of contact pressure between these bodies are established. The nature of stress concentration in the splined hollows of the shaft head is determined. Models and research methods have been developed that make it possible to develop recommendations for design decisions in the design of vehicle suspension systems. The factors are determined that ensure the strength of the torsion shaft at the values of its head diameters close to the diameters of the torsion shaft stem. In the case under consideration, this factor is firstly strength of the torsion shaft head. In particular, it was found that during manufacturing operations there are significant plastic deformations and contact loads in the heads of torsion shafts. This factor is decisive in substantiating the design parameters of torsion shafts. Keywords: torsion shaft; contact interaction; stress-strain state; elastically plastic deformation; suspension system


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