scholarly journals Analysis of concrete deformation diagram, received by different ways of formation, and their separate layers

2019 ◽  
Vol 687 ◽  
pp. 022008
Author(s):  
S A Stel’makh ◽  
E M Shcherban’ ◽  
M G Kholodnyak
Keyword(s):  
Deformation Diagram

Numerical Methods for Solving Physically Nonlinear Problems for Inhomogeneous Thick-Walled Shells

2017 ◽  
Vol 865 ◽  
pp. 325-330 ◽  
Author(s):  
Vladimir I. Andreev ◽  
Lyudmila S. Polyakova
Keyword(s):  
Numerical Method ◽  
Nonlinear Problems ◽  
Successive Approximations ◽  
Method Of Successive Approximations ◽  
Deformation Diagram ◽  
Method Of Solution ◽  
Properties Of Materials ◽  
Physical Fields ◽  
Cylinders And Spheres ◽  
Numerical Method Of Solution

The paper proposes the numerical method of solution the problems of calculation the stress state in thick-walled cylinders and spheres from physically nonlinear inhomogeneous material. The urgency of solved problem due to the change of mechanical properties of materials under the influence of different physical fields (temperature, humidity, radiation, etc.). The deformation diagram describes the three-parameter formula. The numerical method used the method of successive approximations. The results of numerical calculation are compared with the test analytical solutions obtaining the authors with some restrictions on diagram parameters. The obtained results can be considered quite satisfactory.

PHYSICAL PREREQUISITES FOR GAS PERMEABILITY SIMULATION OF MINED ROCK MASS

2021 ◽  
pp. 78-84
Author(s):  
Oleksandr Shashenko ◽  
◽  
Vladyslava Cherednyk ◽  
Natalia Khoziaikina ◽  
Dmitro Shashenko ◽  
...  
Keyword(s):  
Rock Mass ◽  
Physical Model ◽  
Rock Sample ◽  
Coal Mass ◽  
Dynamic Processes ◽  
Deformation Diagram ◽  
Gas Dynamic ◽  
Laboratory Test Results ◽  
Deformation Properties ◽  
Complete Deformation

Purpose. Justification of the gas collectors formation physical model on the basis of research of conformity of permeability of rock mass to the full diagram of rock sample deformation. Methodology consists in sequential analysis of the stages of the complete deformation diagram of the rock specimen under “hard” loading, comparing them with the stages of formation of the high stress zone in front of the lava bottom and statistical analysis of laboratory test results. Results. Based on the rock’s deformation properties analysis and their comparison with the rock sample full deformation diagram, the physical model of formation of gas reservoirs during the development of gas-saturated coal seam is substantiated. Within the solved problem framework, four stages of the complete deformation process are analyzed, namely: elastic, at the limit of strength, out-of-bounds stage and equivoluminal flow zone. The gas collector boundaries, which are the characteristic points of the rock sample deformation diagram in specified deformations mode (the limit of elastic strength and the limit of final strength) are determined. It is proved that the structural and textural features of the coal mass in connection with the course of gas-dynamic processes are manifested in the change in the pores and cracks volume contained in it, which together make the filtration space. Knowledge regarding the transfer of the permeability changes established regularities and free methane accumulation zones formation to the real rock mass, if the process of its forgery is considered as a consistent change of geomechanical states of rocks, is obtained. Scientific novelty lies in the first substantiated possibility of modeling the stress state before the longwall face by equivalent stages of the rock sample destruction in the given deformations mode. Gradual comparative analysis of the internal mechanism of rock samples deformation along the complete deformation diagram allowed establishing causal relationships between geomechanical and gas-dynamic processes in coal mass, and qualitatively characterizing general trends in permeability and volumetric expansion in changes of these samples. Practical value of the work lies in the justification of the principle of construction of a digital geomechanical model for the detection of man-made gas collectors in a mined coal mass.

Characteristics of Dynamic Loading Obtained From Braced Piping Support Under Sinusoidal Shaking Condition

2020 ◽  
Author(s):  
Ryuya Shimazu ◽  
Ichiro Tamura ◽  
Shinichi Matsuura ◽  
Michiya Sakai ◽  
Yohei Ono
Keyword(s):  
Time History ◽  
Maximum Force ◽  
Plastic Behavior ◽  
Deformation Diagram ◽  
Restoring Force ◽  
Maximum Deformation ◽  
Elastic Plastic ◽  
Vibration Tests ◽  
Input Wave

Abstract Loads applied to structures by means of vibration can be classified into load-controlled and displacement-controlled loads. The realistic elastic-plastic behavior of structures subjected to seismic loads is not fully understood, and the classification of the load applied to structures by means of earthquakes is unclear. The failure mode differs depending on the load classification, and thus clarifying the classification of the load applied to the structure is useful for designing the structure. This study clarified the realistic load classification of structures under an elastic-plastic response. Vibration tests were conducted using sinusoidal waves as inputs, and the elastic-plastic behavior of the piping supports undergoing buckling or fatigue failure was obtained. The maximum restoring force and the maximum deformation relationship were obtained from the envelope of the time history data of the test results. In addition, it was shown that the classification of the load could be determined from the maximum force-deformation diagram, even in cases involving buckling and fatigue. In the maximum force-deformation diagram, when the change in the ratio of dynamic restoring force to static restoring force is small, a load-controlled load is applied to the structure because the restoring force of the structure follows the change in the input wave. By contrast, when the change in the ratio of dynamic response displacement to static displacement is small, a displacement-controlled load is applied to the structure because the response displacement of the structure follows the change in the input wave.

scholarly journals Normal Sections Calculation of Bending Reinforced Concrete and Fiber Concrete Elements

2018 ◽  
Vol 7 (3.2) ◽  
pp. 176
Author(s):  
Dmytro Kochkarev ◽  
Tatyana Galinska ◽  
Oleksandr Tkachuk
Keyword(s):  
Reinforced Concrete ◽  
Rectangular Cross Section ◽  
Nonlinear Function ◽  
Fiber Reinforced Concrete ◽  
Deformation Model ◽  
Fiber Reinforced ◽  
Deformation Diagram ◽  
First Case ◽  
Fiber Concrete ◽  
Concrete Elements

The basic principles of the normal sections calculation of reinforced concrete and fiber reinforced concrete bending elements are considered. In the article the power and deformation methods of calculation of reinforced concrete and fiber concrete elements of rectangular cross-section are presented. The deformation model of the calculation of reinforced concrete and fiber concrete elements is presented in the framework of the method of calculation resistance of the section. This method makes possible from the common methodological positions to perform calculations of reinforced concrete and fiber concrete elements. Namely, to select reinforcement and to determine the carring capacity. The proposed deformation model for calculating fiber concrete elements is based on generally accepted preconditions. A hypothesis of plane cross sections is accepted as fair. The deformation diagram of compressed concrete is described by a nonlinear function with established parametric points. Distribution of stresses in stretched concrete is taken rectangular with corresponding coefficients which are taken depending on the type of deformation diagram. Determination of the carring capacity of fiber concrete elements occurs under extreme deformation criteria. Two cases of destruction of the investigated elements are considered. The first case is the destruction due to the achievement of limiting deformations in the concrete of the compressed zone with the simultaneous achievement of the fluidity limit in the working reinforcement. The second case is the destruction due to the achievement of limiting deformations in the concrete of the compressed zone without reaching the fluidity limit in the working reinforcement. Both cases of calculation are reduced to one functional dependence. This avoids the delimitation of different calculation cases. The main no dimensional modifier is the mechanical coefficient of reinforcement. According to the developed method, examples of calculations of reinforced concrete, fiber reinforced concrete elements and fiber concrete elements with longitudinal reinforcement are executed. The possibility of a spread variant design of reinforced concrete and fiber concrete elements is shown. 

Seismic Protection of Structures Using Tuned Mass Dampers with Resettable Variable Stiffness

2012 ◽  
Vol 83 ◽  
pp. 75-84
Author(s):  
Chi Chang Lin ◽  
Tsu Teh Soong
Keyword(s):  
Active Control ◽  
Control Strategy ◽  
Good Control ◽  
Variable Stiffness ◽  
Seismic Protection ◽  
Control Law ◽  
Control Performance ◽  
Deformation Diagram ◽  
Tuned Mass Dampers ◽  
Engineering Structures

Vibration control of civil engineering structures using tuned mass dampers (TMD) is a widely accepted control strategy after numerous analytical and experimental verifications. Although the design and application of traditional linear TMD systems are well developed, nonlinear TMD systems that may lead to better control performance are still in the developmental stage. There are two main problems associated with TMD systems, i.e. (1) detuning effect and (2) excessive stroke of TMD. In order to improve the performance of TMD systems, a novel semi-active TMD named resettable variable stiffness TMD (RVS-TMD) is proposed in this study. The RVS-TMD consists of a TMD and a resettable variable stiffness device (RVSD). The RVSD is composed of a resettable element and a controllable stiffness element. By varying the stiffness element of the RVSD, the force produced by the RVSD can be controlled smoothly through a semi-active control law. By resetting the resettable element, the hysteresis loop of the RVSD can cover all four quadrants in the force-deformation diagram and thus results in more energy dissipation. The harmonic and seismic responses of a building equipped with the RVS-TMD are investigated numerically and compared with those by its active control counterpart and an optimal passive TMD system. The results show that the proposed RVS-TMD system has good control performances as its active control counterpart and is able to alleviate detuning effect and reduce TMD’s stroke.

scholarly journals DIAGRAMS OF VACUUM INSULATING PANEL DEFORMATION DURING COMPRESSION

2019 ◽  
Vol 9 (3) ◽  
pp. 17-21
Author(s):  
Vladimir P. SELYAEV ◽  
Nikolay N. KISELEV ◽  
Oleg V. LIYASKIN
Keyword(s):  
Stress State ◽  
Load Transfer ◽  
Experimental Studies ◽  
Compressive Load ◽  
Deformation Diagram ◽  
Vacuum Insulation ◽  
Floor Slabs ◽  
Wall Panels ◽  
The Relationship ◽  
Deformation Diagrams

The possibility of using vacuum insulation panels (VIP) with a granular filler for the manufacture of threelayer enclosing wall panels, floor slabs and coatings is considered. The results of experimental studies of vacuum insulation panels, carried out with the aim of analytically describing the deformation diagrams of VIP panels under the action of a compressive load, are presented. It has been established: deformative properties of vacuum insulation panels with granular filler do not depend on the size of the filler particles, but depend on the volume content of the filler; a deformation diagram describing the relationship between stresses and relative deformations during compression of a vacuum insulating panel with a granular filler can be approximated by the function G. B. Bülfinger. The results obtained make it possible by calculation to determine the stress state in flat plating sheets during local load transfer.

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