scholarly journals Numerical and experimental studies of deflections of conventional and strengthened reinforced concrete bendable elements under short-term dynamic loading

2021 ◽  
Vol 13 (S) ◽  
pp. 179-192
Author(s):  
Dmitry Yu. SARKISOV ◽  
Georgy I. ODNOKOPYLOV ◽  
Vladimir V. KRYLOV ◽  
Andriy O. ANNENKOV
Keyword(s):  
Shock Wave ◽  
Experimental Investigation ◽  
Reinforced Concrete ◽  
Dynamic Loading ◽  
Software Package ◽  
Building Structures ◽  
Ansys Software ◽  
Short Term ◽  
Actual Problem ◽  
Explicit Dynamics

The relevance of this study is conditioned by the technical complexity of the design solutions for construction projects of ground-based space infrastructure. It is associated with the possibility of special loads in the form of an air shock wave in the event of a launch abort, a fall of a fragment, an emergency shutdown of engines, an air shock wave from the indirect impact of nuclear weapons, seismic loads, accidental cargo falls, terrorist attacks, etc. Such impacts with a high degree of probability lead to damage to building structures and in the future, they need to be reinforced. These building structures must have survivability under special loads and deform without collapsing. Under the dynamic loading, the energy intensity of the bendable structures is important, to determine which it is necessary to know the magnitude of the acting force and deflections. The effective load in a wide class of problems refers to the initial data, and the determination of reliable values of the dynamic deflection of the bendable structure is an actual problem. The purpose of this study is to conduct a numerical and experimental investigation of the deflection of conventional and strengthened reinforced concrete structures under short-term dynamic loading. This study used the following research methods: measurements of deflections and loads by strain measurement, graphical analytic research using Microsoft Excel, numerical calculation in the environment of the Explicit Dynamics module of the Ansys software package. As a result of the study, experimental investigation of conventional and strengthened bendable reinforced concrete elements under short-term dynamic loading was carried out, the values of the effective force and deflections were obtained. The same experiment was modelled in the environment of the Explicit Dynamics module of the Ansys software package. A comparison of the deflection parameters was made, based on the results of numerical and physical experiments on the example of a specific design, which showed satisfactory convergence.

scholarly journals Modeling of formation ring sheet sample from aluminum alloy by elastic medium stamping

2020 ◽  
pp. 30-38
Author(s):  
Konstantin Bobin ◽  
◽  
Pavel Bobin ◽  
Vitaliy Tolmachev ◽  
◽  
...  
Keyword(s):  
Experimental Data ◽  
Aluminum Alloy ◽  
Elastic Medium ◽  
Software Package ◽  
Static Problem ◽  
Ansys Software ◽  
Forming Process ◽  
Good Convergence ◽  
Explicit Dynamics ◽  
Sheet Sample

The forming process in tank with elastic structure of ring sheet sample from aluminum alloy D16AM with flanges on internal and external sides was modulated. The numerical modulation by using the module “explicit dynamics” of the “ANSYS” software package was performed. The features of modeling the quasi static problem of forming a sheet part by using the elastic medium was described. The simulation results are compared with experimental data obtained in previous studies of the authors. The possibility of using the “explicit dynamics” module of the “ANSYS” software package for modeling the forming of sheet parts by an elastic medium has been confirmed. Calculations of the required press force for stamping ring sheet samples made of D16AM alloy with an elastic medium showed good convergence with experimental data.

scholarly journals Eigenfrequency spectrum of the reinforced concrete cantilever beam

2019 ◽  
Vol 91 ◽  
pp. 02031
Author(s):  
Pavel Morozovskiy ◽  
Ilya Kulish ◽  
Nikita Kryzhanovskii ◽  
Vladimir Filatov ◽  
Marina Romanovich
Keyword(s):  
Reinforced Concrete ◽  
Cantilever Beam ◽  
Software Package ◽  
Dynamic Loads ◽  
Building Structures ◽  
Eigen Frequencies ◽  
Eigenfrequency Spectrum ◽  
Eigen Frequency

For the calculation of building structures under the influence of external dynamic loads, it is necessary to know the eigen frequencies of the structures themselves in order to prevent such a phenomenon as resonance. Steel has distinctive properties from concrete, so its consideration is necessary to determine the eigen frequency of the whole structure. This article presents the calculation of the cantilever beam analytically and in the software package Abaqus for linear and volumetric problems with the interaction of concrete and reinforcement. Due to the reinforcement, the beam eigen frequencies differ from the eigen frequency of the conventional rigidly fixed rod, as evidenced by the results of the calculation.

scholarly journals Experimental study of beams on yielding supports with thrust

2018 ◽  
Vol 143 ◽  
pp. 01016
Author(s):  
Oleg Kumpyak ◽  
Zaur Galyautdinov ◽  
Daud Galyautdinov
Keyword(s):  
Reinforced Concrete ◽  
Crack Resistance ◽  
Dynamic Loading ◽  
Experimental Studies ◽  
Concrete Structures ◽  
Horizontal Displacement ◽  
Positive Outcome ◽  
Reinforced Concrete Beam ◽  
Reinforced Concrete Structures ◽  
Short Term

The design of reinforced concrete structures which are subjected to static and intensive dynamic loading requires taking into account the occurrence of thrust reaction resulting in significant increase in strength and crack resistance. Application of yielding supports for the purpose of increasing the energy capacity of structures shall also be considered. The present research aims to define feasibility of yielding supports application in thrust structures. The paper presents the outcomes of experimental studies of reinforced concrete beam structures on yielding supports subjected to thrust under static and short-term dynamic loading. The influence of thrust on the strength, deformation property and crack resistance of reinforced concrete structures under static and short-term dynamic loading was investigated. The combined use of yielding supports and the restriction of horizontal displacement of the support contour were also considered in the study. Research results testify on the positive outcome when yielding supports are applied in the structures subjected to thrust.

Strength of Normal and Inclined Sections of Bent Reinforced Concrete Elements with Zone Reinforcement Made of Steel Fiber

2022 ◽  
Vol 906 ◽  
pp. 7-15
Author(s):  
Dmitry Utkin
Keyword(s):  
Reinforced Concrete ◽  
Dynamic Loading ◽  
Calculation Method ◽  
Steel Fiber ◽  
Experimental Studies ◽  
Concrete Structures ◽  
Dynamic Loads ◽  
Reinforced Concrete Structures ◽  
Short Term ◽  
Concrete Elements

On the basis of theoretical and experimental studies, the prerequisites and the method of calculation of bent and compressed-curved reinforced concrete structures with zone reinforcement made of steel fiber, working under static and short-term dynamic loads, are formulated. In the developed method for calculating the strength of normal and inclined sections, a nonlinear deformation model is implemented, which is based on the actual deformation diagrams of materials. The developed calculation method is brought to the program of calculation of reinforced concrete structures with zone reinforcement of steel fiber under short-term dynamic loading, taking into account the inelastic properties of materials. The numerical studies made it possible to determine the influence of various parameters of steel-fiber reinforcement on the strength of reinforced concrete elements. To confirm the main results of the developed calculation method, experimental studies of reinforced concrete beam structures reinforced with conventional reinforcement and a zone steel-fiber layer are planned and carried out. Experimental studies were carried out under static and short-term dynamic loads. As a result of the conducted experiments, data were obtained that characterize the process of destruction, deformation and cracking of steel-reinforced concrete elements under such types of loading. The dependences of changes in the energy intensity of reinforced concrete structures with zone reinforcement made of steel fiber in the compressed and stretched cross-section zones under dynamic loading are obtained. The effectiveness of the use of fiber reinforcement of normal and inclined sections of bent and compressed-curved elements to improve the strength and deformative.

scholarly journals Nonlinear calculation of reinforced concrete structures to the impact of the air shock wave

Vestnik MGSU ◽  
2019 ◽  
pp. 33-45 ◽  
Author(s):  
Anton Y. Savenkov ◽  
Oleg V. Mkrtychev
Keyword(s):  
Numerical Simulation ◽  
Shock Wave ◽  
Reinforced Concrete ◽  
Nonlinear Dynamic ◽  
Software Package ◽  
Crack Opening ◽  
Concrete Structures ◽  
Reinforced Concrete Structures ◽  
Advantages And Disadvantages ◽  
The Impact

Introduction. Researched methods of accounting for the nonlinear operation of reinforced concrete structures on the example of an industrial structure, when exposed to an air shock wave using modern software systems based on the finite element method. The calculation of reinforced concrete construction to the impact of an air shock wave, if no increased requirements for tightness are presented to it, in accordance with current regulatory documents, must be carried out taking into account the elastic-plastic work, crack opening in the stretched zone of concrete and plastic deformations of reinforcement are allowed. Reviewed by new coupling approach to determining the dynamic loads of a shock wave, implemented in the LS-DYNA software package, which allows to take into account the effects of a long-range explosion and wave-wrapping around a structure. Materials and methods. The study of the stress-strain state of the structures was carried out using numerical simulation. For the nonlinear equivalent-static method, a step-by-step calculation algorithm is used, with gradual accumulation and distribution of stresses, implemented in the LIRA-SAPR software package. For the nonlinear dynamic method, the Lagrangian-Eulerian formulation is used using the methods of gas dynamics in the LS-DYNA software package. Results. As a result of numerical simulation, the following was done analysis of existing methods of nonlinear calculations; analysis of the existing loads during the flow of shock waves around the structure; analysis of the forces and movements in the bearing elements, as well as pictures of the destruction of concrete and reinforcement. Conclusions. According to the results of the comparison of the two approaches, conclusions are drawn about the advantages and disadvantages of the methods. Advantages of nonlinear dynamic calculation methods are noted compared to the equivalent-static ones. Use of the combined approach to the description of the shock wave front gives a reduction in time and allows us to describe the interaction of the wave with the structure with sufficient accuracy. The findings indicate the relevance of the study and provide an opportunity to move to more reasonable computational models.

scholarly journals NUMERICAL SIMULATION OF YIELDING SUPPORTS IN THE SHAPE OF ANNULAR TUBES UNDER STATIC AND SHORT-TERM DYNAMIC LOADING

2017 ◽  
Vol 13 (4) ◽  
pp. 103-113 ◽  
Author(s):  
Oleg G. Kumpyak ◽  
Nikita V. Mescheulov
Keyword(s):  
Dynamic Loading ◽  
Economic Losses ◽  
Building Structures ◽  
Short Term ◽  
Linear Character ◽  
Numerical Studies ◽  
Condensed Explosives ◽  
Fuel Mixtures ◽  
Prevention Methods ◽  
The Given

Occurrence of extreme man-made impacts on buildings and structures has become frequent lately as a consequence of condensed explosives or explosive combustion of gas- vapor or air-fuel mixtures. Such accidents involve large human and economic losses, and their prevention methods are not always effective and reasonable. The given research aims at studying the way of enhancing explosion safety of building structures by means of yielding supports. The paper presents results of numerical studies (finite element, 3D nonlinear) of strength and deformability of yielding supports in the shape of annular tubes under static and short-term dynamic loading. The degree of influence of yielding supports was assessed taking into account three peculiar stages of deformation: elastic; elasto-plastic; elasto-plastic with hardening. The methodology for numerical studies performance was described. It was established that rigidity of yielding supports influences significantly their stress-strain state. The research determined that with increase of deformable elements rigidity dependency between load and deformation of yielding supports in elastic and plastic stages have linear character. Significant reduction of dynamic response and increase of deformation time of yielding supports was observed by increasing the plastic component. Therefore it allows assuming on possibility of their application as supporting units in reinforced concrete constructions

scholarly journals Analysis of changes in the survivability of building structures reinforced after an emergency dynamic impact in the context of assessing the security of buildings in the oil and gas industry

2021 ◽  
Vol 8 (12) ◽  
pp. 25-35
Author(s):  
Sarkisov et al. ◽  
Keyword(s):  
Shock Wave ◽  
Oil And Gas ◽  
Energy Parameter ◽  
Oil And Gas Industry ◽  
Building Structures ◽  
Building Structure ◽  
Wave Loads ◽  
Wave Load ◽  
Short Term ◽  
The Impact

The relevance of the subject matter is conditioned by the technical complexity of the oil and gas facilities due to the increase in the volume and rate of raw materials production, which may be affected by shock-wave loads in emergency situations. The causes of the impact can be explosions, heavy cargo falls, terrorist attacks, natural and anthropogenic disasters, etc. These situations are very likely to cause significant damage to the building structures of industrial facilities, which necessitates their reinforcement. For further safe operation of the facility, reinforced structures must have survivability under repeated impacts no less than before the reinforcement. Given the fact that the survivability of buildings is a complex characteristic influenced by many factors, and it itself is a component of the security of a hazardous production facility, research in this area is topical. The purpose of the study is to test the developed method for assessing the survivability of a building structure under short-term shock-wave load based on the energy parameter and to analyze the results obtained in the context of assessing the security of critical oil and gas facilities. Research methods: Measurement of accelerations, deflections, and loads by strain measurement methods, graphoanalytical method of study using the Microsoft Excel software. A method for assessing the level of survivability of a building structure under shock-wave loading for critical oil and gas facilities using the survivability coefficient is developed. Using specific tests of conventional and cage-reinforced bending concrete elements for short-term dynamic load, the values of the specified coefficient are obtained. The values are compared and conclusions are drawn.

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