scholarly journals The concept of a prefabricated structure for protection of critical infrastructure facilities

2018 ◽  
Vol 67 (2) ◽  
pp. 133-144
Author(s):  
Kamil Sobczyk ◽  
Ryszard Chmielewski ◽  
Krzysztof Duda
Keyword(s):  
Reinforced Concrete ◽  
Computational Analysis ◽  
Critical Infrastructure ◽  
High Mobility ◽  
Dynamic Loads ◽  
Protective Structure ◽  
Internal Forces ◽  
Prefabricated Structure ◽  
Building Engineering

The paper presents the concept of a protective structure in the form of a prefabricated reinforced concrete protective dome intended for protection of a single critical infrastructure facility [1]. Unlike non-movable cast-in-place reinforced concrete structures, the protective structure can be assembled and disassembled repeatedly with the use of dedicated joining sockets. To provide the concept with a high mobility, the dimensions of single modules of the prefabricated reinforced concrete protective dome meet the transport limits dictated by the horizontal and vertical clearance of roads. A numerical computational analysis facilitated a determination of the distribution of internal forces in the protective stricture and dimensioning of the required reinforcement system [3]. The computations included standardized cases of steady and dynamic loads, and combinations thereof, complete with parameters of dynamic loads from an explosion impulse. Keywords: building engineering, protective structure, prefabricated dome

scholarly journals The design model of reinforced concrete beam formed by the field of cracks directions

2019 ◽  
Vol 97 ◽  
pp. 04017
Author(s):  
Sofia Kurnavina ◽  
Ilya Tsatsulin
Keyword(s):  
Differential Equation ◽  
Reinforced Concrete ◽  
Concrete Beam ◽  
Longitudinal Force ◽  
Reinforced Concrete Beam ◽  
Equation Of Motion ◽  
Dynamic Loads ◽  
Force Ratio ◽  
Internal Forces ◽  
Static And Dynamic Loads

Now the design of reinforced concrete constructions for static and dynamic loads with regard to the elastoplastic resistance diagrams of materials is widely used. The model of a reinforced concrete beam is proposed, which consists of trapezoidal elements formed by the field of cracks directions. The theoretical angle of inclination of a crack at any point of a beam has been determined on the basis of minimum of external load, necessary for its formation, which has been obtained from the equation of energy balance. The deflections of each point of a beam have been obtained by solving a differential equation of motion at each step the account. The strains in any fiber of normal and inclined sections have been determined according to the hypothesis of bilinear sections. The stresses in concrete and reinforcement have been obtained with the help of the variable elastoplastic stress-strain curves «σ-ε». The failure mechanism of a beam has been determined on a basis of the transverse to longitudinal force ratio in compressed area of concrete. The internal forces have been determined with the help of numerical section height integration of stresses and from the equation of balance of elements above the crack.

scholarly journals Analytical Method for Determination of Internal Forces of Mechanisms and Manipulators

Robotics ◽  
2018 ◽  
Vol 7 (3) ◽  
pp. 53 ◽  
Author(s):  
Muratulla Utenov ◽  
Tarek Sobh ◽  
Zhumadil Baigunchekov ◽  
Saltanat Zhilkibayeva ◽  
Sarosh Patel
Keyword(s):  
Cross Sections ◽  
Discrete Model ◽  
Discrete Models ◽  
Dynamic Loads ◽  
Dynamic Equations ◽  
Analytical Determination ◽  
Kinematic Characteristics ◽  
Internal Forces ◽  
Rigid Joints

This paper presents a theory for the analytical determination of internal forces in the links of planar linkage mechanisms and manipulators with statically determinate structures, considering the distributed dynamic loads. Linkage mechanisms and manipulators were divided into elements and joints. Discrete models were created for both the elements and the entire mechanism. The dynamic equations of equilibrium for the discrete model of the elements and the hinged and rigid joints, under the action of longitudinal and transverse distributed dynamic trapezoidal loads, were derived. In the dynamic equations of the equilibrium of the discrete model of the elements and joints, the connections between the components of the force vector in the calculated cross-sections and the geometric, physical, and kinematic characteristics of the element were established for its plane-parallel motion. According to the developed technique, programs were created in the Maple system, and animations of the motion of the mechanisms were produced. The links were constructed with the intensity of transverse- and longitudinal-distributed dynamic loads, bending moments, and shearing and normal forces, depending on the kinematic characteristics of the links.

Improvement Of Curvilinear Diagrams Of Concrete Deformation

2019 ◽  
pp. 99-104
Keyword(s):  
Reinforced Concrete ◽  
Peak Load ◽  
Experimental Studies ◽  
Concrete Structures ◽  
Deformation Model ◽  
Reinforced Concrete Structures ◽  
Significant Difference ◽  
Deformation Diagrams

Problems when calculating reinforced concrete structures based on the concrete deformation under compression diagram, which is presented both in Russian and foreign regulatory documents on the design of concrete and reinforced concrete structures are considered. The correctness of their compliance for all classes of concrete remains very approximate, especially a significant difference occurs when using Euronorm due to the different shape and sizes of the samples. At present, there are no methodical recommendations for determining the ultimate relative deformations of concrete under axial compression and the construction of curvilinear deformation diagrams, which leads to limited experimental data and, as a result, does not make it possible to enter more detailed ultimate strain values into domestic standards. The results of experimental studies to determine the ultimate relative deformations of concrete under compression for different classes of concrete, which allowed to make analytical dependences for the evaluation of the ultimate relative deformations and description of curvilinear deformation diagrams, are presented. The article discusses various options for using the deformation model to assess the stress-strain state of the structure, it is concluded that it is necessary to use not only the finite values of the ultimate deformations, but also their intermediate values. This requires reliable diagrams "s–e” for all classes of concrete. The difficulties of measuring deformations in concrete subjected to peak load, corresponding to the prismatic strength, as well as main cracks that appeared under conditions of long-term step loading are highlighted. Variants of more accurate measurements are proposed. Development and implementation of the new standard GOST "Concretes. Methods for determination of complete diagrams" on the basis of the developed method for obtaining complete diagrams of concrete deformation under compression for the evaluation of ultimate deformability of concrete under compression are necessary.

Determination of Internal Forces in End Plates of Simple End Plate Joints

2009 ◽  
Vol 12 (-1) ◽  
pp. 83-94
Author(s):  
Stefan Dominikowski ◽  
Piotr Bogacz
Keyword(s):  
End Plate ◽  
Internal Forces

EXPERIMENTAL STUDIES OF REINFORCED CONCRETE STRUCTURES WITH CROSS-SHAPED SPATIAL CRACK UNDER TORSION WITH BENDING

2020 ◽  
Vol 92 (6) ◽  
pp. 13-25
Author(s):  
Vl.I. KOLCHUNOV ◽  
◽  
A.I. DEMYANOV ◽  
M.M. MIHAILOV ◽  
◽  
...  
Keyword(s):  
Reinforced Concrete ◽  
Experimental Determination ◽  
Calculation Method ◽  
Experimental Studies ◽  
Concrete Structures ◽  
Design Parameters ◽  
Reinforced Concrete Structures ◽  
Experimental Scheme

The article offers a method and program for experimental studies of reinforced concrete structures with cross-shaped spatial crack under torsion with bending, the main purpose of which is to check the design assumptions and experimental determination of the design parameters of the proposed calculation method. The conducted experimental studies provide an opportunity to test the proposed calculation apparatus and clarify the regularities for determining deflections, angles of rotation of extreme sections, and stresses in the compressed zone of concrete. For analysis, the article presents a typical experimental scheme for the formation and development of cracks in the form of a sweep, as well as characteristic graphs of the dependence of the angles of rotation of end sections.

Modeling of Dynamic Loads on the Polished Rod of Pumping Unit in Case of Mulfunction of Rod Pump Operating

2014 ◽  
Vol 10 ◽  
pp. 95-101
Author(s):  
A.S. Topolnikov
Keyword(s):  
Multiphase Flow ◽  
Satisfactory Agreement ◽  
Model Simulation ◽  
Theoretical Modeling ◽  
Dynamic Loads ◽  
Plunger Pump ◽  
Proposed Model ◽  
Pumping Unit ◽  
Polished Rod

The paper presents the results of theoretical modeling of joined movement of pump rods and plunger pump and multiphase flow in a well for determination of dynamic loads on the polished rod of pumping unit. The specificity of the proposed model is the possibility of taking into account for complications in rod pump operating, such as leakage in valve steam, presence of gas and emulsion, incorrect fitting of plunger inside the cylinder pump. The satisfactory agreement of results of the model simulation with filed measurements are obtained.

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