scholarly journals A comparative analysis of the stress-strain state of disc specimens in assessing the structural strength of materials

2022 ◽  
Vol 10 (1) ◽  
pp. 25-34 ◽  
Author(s):  
L.B. Tsvik ◽  
E.V. Zenkov
Keyword(s):  
Comparative Analysis ◽  
Strain State ◽  
Structural Strength ◽  
Geometrical Parameters ◽  
Principal Stresses ◽  
Stress Strain ◽  
Strength Of Materials ◽  
Stress Strain State ◽  
Materials Used ◽  
Real Type

A study of the stress-strain state (SSS) of disc specimens has been conducted when testing specimens with stress concentrators (grooves). The research has shown that the truncation of circular discs along two symmetrical chords makes it possible to change the type (the ratio of principal stresses) of SSS that occurs at the destruction site. Therefore, these specimens can be used to assess the structural strength of materials on standard single-drive testing machines, taking into account the real type of SSS that occurs in the bearing elements of machines. The results of numerical SSS modeling have been used to build the dependences of the SSS type and level on geometric parameters of specimens. Geometrical parameters can be chosen for a certain SSS type to assess both the static and fatigue strengths of materials used in the manufacture of bearing elements.

scholarly journals Stress-Strain State of a Cylindrical Shell of a Tunnel Using Construction Stage Analysis

2019 ◽  
Vol 21 (3) ◽  
pp. 72-76
Author(s):  
Sergey B. Kosytsyn ◽  
Vladimir Y. Akulich
Keyword(s):  
Cylindrical Shell ◽  
Comparative Analysis ◽  
Static Analysis ◽  
Strain State ◽  
Computational Models ◽  
Stress Strain ◽  
Construction Stage ◽  
Stress Strain State ◽  
Slurry Shield ◽  
Stage Analysis

The work is aimed at research of the stress-strain state of a cylindrical shell of a tunnel using the non-linear static analysis and construction stage analysis. Research is carried out on the example of determining the stress-strain state of the tubing (shells) of the main line tunnel, constructed using a tunnel powered complex (slurry shield). Based on obtained results, a comparative analysis of the computational models with the corresponding conclusions is presented.

scholarly journals Comparison analysis of using micrometers and strain gauges for measuring deformations and loads in the method of monitoring the stress-strain state

2021 ◽  
Vol 18 (3) ◽  
pp. 71-75
Author(s):  
M. O. Lobovskiy ◽  
◽  
A. L. Tukkiya ◽  
P. A. Pyatkin ◽  
◽  
...  
Keyword(s):  
Comparative Analysis ◽  
Strain Gauge ◽  
Laboratory Tests ◽  
Strain State ◽  
Field Tests ◽  
Strain Gauges ◽  
Construction Site ◽  
Comparison Analysis ◽  
Stress Strain ◽  
Stress Strain State

The micrometer method for measuring deformations and loads in bar elements has proved to be effective not only in laboratory tests, but also in field tests on a real construction site. Having carried out a comparative analysis of the method proposed by the authors for monitoring the stress-strain state (SSS) with the strain gauge method which is widely used at present, the authors have proved that the method for measuring deformations and loads using a micrometer is not inferior in accuracy to the strain gauge method, although it is much cheaper.

Research of opening reliability of blast easily disposable systems with honeycomb polycarbonate sheets by finite elements method

2020 ◽  
pp. 107-115
Author(s):  
Yu.Yu. Pidhoretskyi ◽  
Keyword(s):  
Finite Elements ◽  
Strain State ◽  
Numerical Algorithms ◽  
Honeycomb Structure ◽  
Geometrical Parameters ◽  
Stress Strain ◽  
Stress Strain State ◽  
Relief Elements ◽  
Explosion Overpressure ◽  
Applied Approach

In the article, the author presents results of mathematical modeling of operation of the venting relief structures made of honeycomb polycarbonate sheets and fixed in the standard window profiles, under the effect of explosion. In order to reproduce the explosion effect on venting relief structures, an approach to modeling dynamic systems was applied, which used a finite element method to approximate the basic general equations of dynamics added by the equations of the stress-strain state of a solid body. The applied approach differs by reproduction of the explosion process impact on the venting relief structures of this type by using equations which describe the motion of the dynamic system with accounting a contact interaction with the friction of honeycomb polycarbonate sheets and corresponding surfaces of the standard window profile locks. The honeycomb structure of the polycarbonate sheet was modeled by appropriate finite elements with considering the polycarbonate elastic properties. In order to implement numerical algorithms of this approach, a program code of the LS-DYNA computer system was used. The conducted numerical experiment on reproducing the explosion effect on the relief elements of this type of the venting relief structures made it possible to trace all stages of the honeycomb polycarbonate sheets deforming and moving under the action of explosion up to the exit of their edges from the window profile locks with the study of the corresponding stress-strain state parameters. By using this approach, reliably disclosure of the venting relief structures based on honeycomb polycarbonate sheets was investigated, and conditions for their reliable disclosure were identified with considering geometrical parameters of such type of venting relief structures opening and thickness of the honeycomb polycarbonate sheets. Results of the research have shown that reliable disclosure of the honeycomb polycarbonate sheets occurs within the range of the explosion overpressure, hence, confirming the effectiveness of such type of the venting relief structures used for protecting buildings against the explosion action.

scholarly journals INVESTIGATION OF STRESS-STRAIN STATE OF CYLINDRICAL BODY OF MODIFIED HDPE

2019 ◽  
Vol 62 (7) ◽  
pp. 118-122
Author(s):  
Stepan V. Litvinov ◽  
Lyubov I. Lesniak ◽  
Serdar B. Yazyev ◽  
Ivan M. Zotov
Keyword(s):  
Ionizing Radiation ◽  
Strain State ◽  
Polymeric Materials ◽  
Cylindrical Body ◽  
Rheological Parameters ◽  
Scientific School ◽  
Mechanical Parameters ◽  
Principal Stresses ◽  
Stress Strain ◽  
Stress Strain State

The change in the stress-strain state over time in structures and their elements from polymeric materials can be quite substantial. This is due to the pronounced rheology of the polymers. One of the most accurate laws of stress-strain bond is generalized nonlinear Maxwell-Gurevich equation, which takes into account three rheological parameters: the modulus of elasticity, the velocity modulus and the coefficient of initial relaxation viscosity. A significant influence on the physico-mechanical parameters of the polymer is also exerted by various factors: the presence of a temperature field and ionizing radiation, the presence of additives in the polymer and so on. The paper presents the results of mathematical modeling of a disc made of high-density polyethylene (HDPE) in an axisymmetric setting under the influence of mechanical axial pressure. This model is chosen because of the most frequent use of HDPE irradiated and with additives in medicine, including for the manufacture of orthopedic prostheses. Different compositions of HDPE are considered: under the influence of ionizing radiation, with additives of hydroxyapatite and with their combined effect. All physico-mechanical parameters of HDPE (dose of ionizing radiation and the fraction of hydroxyapatite injected) are described by mathematical expressions obtained in the scientific school of Professor B.M. Yazyev on the basis of an analysis of the corresponding polymer relaxation curves. The results of the solution of the problem have shown that the basic stresses (radial, circumferential and axial) vary in the course of time in different ways. The growth of the value of the primary basic stresses can be 2-2.5 times. If the analysis is carried out on the main stresses, then their value increases by approximately 1.5 times. Also, the change in the principal stresses is observed even when it is not observed for the basic stresses.

scholarly journals Numerical research of horizontally weighted bases from hollow circular piles with the reduced step

2016 ◽  
Vol 4 (2) ◽  
pp. 0-0
Author(s):  
Светлана Ямаева ◽  
Svetlana Yamaeva ◽  
Олег Денисов ◽  
Oleg Denisov
Keyword(s):  
Comparative Analysis ◽  
Computational Model ◽  
Numerical Simulations ◽  
Numerical Investigation ◽  
Strain State ◽  
Full Scale ◽  
Stress Strain ◽  
Stress Strain State ◽  
Numerical Research ◽  
Full Scale Tests

The results of numerical investigation of the stress-strain state of subgrade groups of hollow circular piles with diameters of less than three step under the action of horizontal loads. Shows the effect of pitch on piles move horizontally loaded the bases and a comparative analysis of the nature of their work with full-scale tests and numerical simulations. Pseudoplane used computational model of the foundation for the theory of local deformations and linearly deformable half.

scholarly journals Stress-strain state of a three-layer cylindrical shell under internal axisymmetric pulse load

2020 ◽  
pp. 145-151
Author(s):  
Viktor Gaidaichuk ◽  
Kostiantyn Kotenko
Keyword(s):  
Finite Element ◽  
Cylindrical Shell ◽  
Strain State ◽  
Layer Structure ◽  
Three Dimensional ◽  
Pulse Load ◽  
Geometrical Parameters ◽  
Time Interval ◽  
Stress Strain ◽  
Stress Strain State

The problem of dynamic deformation of a three-layer cylindrical shell under non-stationary loads in the case of rigid clamping of the shell ends is considered. The article presents the results of assessing the stress-strain state of a three-layer cylindrical shell, taking into account its structural feature, the ratio of the sheathing thickness and the physical and mechanical characteristics of a one-piece polymer filler. Calculations were performed by software complex Nastran. The values of displacements and stresses were calculated by the algorithm of direct transient dynamic process. The step duration of the time interval was 0.0000025 s, and the total number of steps was 200. The choice of the type of three-dimensional finite element was due to obtaining more detailed and accurate calculation results. The finite element model included 19000 three-dimensional finite elements and numbered 20800 nodes. The influence of geometrical parameters of shell layers with different physical and mechanical properties of one-piece filler on the stress-strain state under axisymmetric internal impulse load is investigated. Numerical results on the dynamics of the three-layer structure, obtained by the finite element method, allow to characterize the stress-strain state of the three-layer elastic structure of the cylindrical type at any time in the studied time interval. Optimization of the shell design is recommended. Changing the ratio of the thickness of the internal and external shells of the shell significantly affects the stress-strain state of the shell and its performance. Increasing the thickness of the internal layer of the shell significantly contributes to the increase of the latter. Comparison of the given results with materials of other similar researches and positions, testify to objectivity of the made approach.

Research the process of cold punching of hex nut blanks of increased height

2019 ◽  
Vol 75 (8) ◽  
pp. 979-984
Author(s):  
I. G. Shubin ◽  
A. A. Kurkin ◽  
A. R. Bazykov ◽  
F. A. Stolyarov
Keyword(s):  
Strain State ◽  
Metal Flow ◽  
Geometrical Parameters ◽  
Stress Strain ◽  
Industrial Testing ◽  
Stress Strain State ◽  
Metal Deformation ◽  
3D Software ◽  
Through Hole ◽  
Power Costs

The high nuts withstand increased load for expansion, facilitating its even distribution along the bolt length. The process of increased height nut blanks plastic deformation characterized by uneven metal flow and changing of stressed state by the blank section. In the process of closed-die stamping of such nuts a risk of their geometry distortion arises. Results of study of the process of production a hex nut of increased height presented. The object of the research was to study the process of the metal deformation when broach a hole for thread in a hexagonal nut blank of increased height. To simulate the stress-strain state, the QForm-3D software package was chosen, which made it possible to predict with sufficient accuracy the metal flow in the blank, calculate the deformation forces and determine the stresses that occur in the tool. The models of the blank and the tool were created in the Compass 3D program without internal and external defects. When performing the work, the parameters of the stress-strain state of a hexagonal nut blank of increased height were calculated. The simulation results showed the need to change the geometry of the end part of the punch to a conical one with an angle of 150 degrees and a reduction in the size of the baffle height from 10.4 mm to 5.4 mm. The adopted changes allowed to reduce the energy and power costs of forming a through hole for the threads. Industrial testing confirmed the correctness of the calculations. Nuts with edges perpendicular to its base and the required geometrical parameters were obtained.

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