scholarly journals Underground main pipeline behaviour under a travelling impulse in the form of a triangle

2021 ◽  
Vol 264 ◽  
pp. 01006
Author(s):  
Barna Rakhmankulova ◽  
Sayibdjan Mirzaev ◽  
Rakhmatjon Khusainov ◽  
Saparboy Khusainov
Keyword(s):  
Wave Front ◽  
Viscoelastic Model ◽  
Elastic Interaction ◽  
Viscosity Coefficient ◽  
Underground Pipeline ◽  
Main Pipeline ◽  
Soil System ◽  
Maximum Deformation ◽  
Viscous Interaction ◽  
Deformed State

The article presents an analysis of the dynamic response of an underground main pipeline under the action of a longitudinal wave, propagating in soil along the pipe. It is assumed that the elastic pipe has a finite length. A linear viscoelastic model of the "pipe-soil" system interaction is considered. The influence of a pulse in the form of a triangle on the deformed state of an underground main pipeline is investigated. The article presents a comparative analysis of the results obtained for some values of the coefficients of elastic and viscous interaction, the propagation velocity, and the duration of the pulse. In the case of elastic interaction of the "pipe-soil" system, the reflection of the wave propagating in the underground pipeline on the boundaries of the pipeline when it coincides with the wave propagating in the soil leads to an increase in the maximum deformation of the underground pipeline, the value of deformation can double. The viscosity coefficient of interaction at the pipe-soil system contact leads to the wave front attenuation in the underground pipeline. For soils with the coefficient of viscous interaction higher than 100 kN∙s/m2, this leads to complete attenuation of the bursts at the wave front in the pipeline. The influence of the wave propagation in soil on the deformation values at the wave front was also studied.

Seismic stability of the underground main pipeline

2011 ◽  
Vol 8 (1) ◽  
pp. 275-286
Author(s):  
R.G. Yakupov ◽  
D.M. Zaripov
Keyword(s):  
Laplace Transformation ◽  
Seismic Waves ◽  
Generalized Functions ◽  
Seismic Stability ◽  
Main Pipeline ◽  
Motion Equations ◽  
Numerical Example ◽  
Earthquake Force ◽  
Deformed State

The stress-deformed state of the underground main pipeline under the action of seismic waves of an earthquake is considered. The generalized functions of seismic impulses are constructed. The pipeline motion equations are solved with used Laplace transformation by the time. Tensions and deformations of the pipeline have been determined. A numerical example is reviewed. Diagrams of change of the tension depending on earthquake force are provided in earthquake-points.

Simulation of non-stationary thermal fields from a buried thermally insulated pipeline and its diagnostics

2007 ◽  
Vol 5 ◽  
pp. 127-132
Author(s):  
N.A. Vaganova
Keyword(s):  
Thermal Imaging ◽  
Software Package ◽  
Clay Soil ◽  
Underground Pipeline ◽  
Main Pipeline ◽  
Factors Affecting ◽  
Thermal Fields ◽  
Thermal Imaging Equipment ◽  
Principal Possibility ◽  
Significant Factors

To detect damage to the underground pipeline, a mathematical model, allowing to take into account the most significant Factors affecting the distribution of temperature on the day surface. To implement this model, a software package has been developed and results of numerical calculations. With the help of these calculations, in particular, It is established that modern thermal imaging equipment has a principal possibility to determine an unauthorized frame in the main pipeline at a depth of two meters in clay soil.

scholarly journals An Analytical Solution for Non-Linear Viscoelastic Impact

Mathematics ◽  
2021 ◽  
Vol 9 (16) ◽  
pp. 1849
Author(s):  
Stelian Alaci ◽  
Constantin Filote ◽  
Florina-Carmen Ciornei ◽  
Oana Vasilica Grosu ◽  
Maria Simona Raboaca
Keyword(s):  
Analytical Solution ◽  
Hysteresis Loop ◽  
Viscoelastic Model ◽  
First Integral ◽  
Coefficient Of Restitution ◽  
Contact Period ◽  
Maximum Deformation ◽  
Impact Parameters ◽  
Simplified Algorithm ◽  
The Moment

The paper presents an analytical solution for the centric viscoelastic impact of two smooth balls. The contact period has two phases, compression and restitution, delimited by the moment corresponding to maximum deformation. The motion of the system is described by a nonlinear Hunt–Crossley equation that, when compared to the linear model, presents the advantage of a hysteresis loop closing in origin. There is only a single available equation obtained from the theorem of momentum. In order to solve the problem, in the literature, there are accepted different supplementary hypotheses based on energy considerations. In the present paper, the differential equation is written under a convenient form; it is shown that it can be integrated and a first integral is found—this being the main asset of the work. Then, all impact parameters can be calculated. The effect of coefficient of restitution upon all collision characteristics is emphasized, presenting importance for the compliant materials, in the domain of small coefficients of restitution. The results (variations of approach, velocity, force vs. time and hysteresis loop) are compared to two models due to Lankarani and Flores. For quasi-elastic collisions, the results are practically the same for the three models. For smaller values of the coefficient of restitution, the results of the present paper are in good agreement only to the Flores model. The simplified algorithm for the calculus of viscoelastic impact parameters is also presented. This algorithm avoids the large calculus volume required by solving the transcendental equations and definite integrals present in the mathematical model. The method proposed, based on the viscoelastic model given by Hunt and Crossley, can be extended to the elasto–visco–plastic nonlinear impact model.

The impact of temperature change on stress deformed state of a main pipeline surrounded by a viscous medium and affected by thrusts and dislocations of the Earth’s crust

2006 ◽  
Vol 4 ◽  
pp. 32-40
Author(s):  
M.I. Davletov ◽  
Yu.V. Kazantsev ◽  
A.G. Khakimov
Keyword(s):  
Internal Pressure ◽  
Temperature Change ◽  
Viscous Medium ◽  
Earth’S Crust ◽  
Main Pipeline ◽  
Constraint Forces ◽  
Deformed State ◽  
Earth's Crust ◽  
The Impact ◽  
Excess Internal Pressure

The present investigation concerns the movement and stress deformed state of a main pipeline with excess internal pressure surrounded by a highly viscous medium under changing temperature and also in the case of thrusts and dislocations of the Earth’s crust. Account is taken of constraint forces occurred due to excess internal pressure and temperature change.

Study on Correlation between the Starch Content of Potato Tuber and its Viscoelastic Characteristics

2012 ◽  
Vol 591-593 ◽  
pp. 2545-2550
Author(s):  
Wen Bin Guo ◽  
Chun Guang Wang ◽  
Jing Jing Gao
Keyword(s):  
Potato Tuber ◽  
Starch Content ◽  
Viscoelastic Model ◽  
Viscosity Coefficient ◽  
Potato Tubers ◽  
Obvious Effect ◽  
Viscoelastic Parameters ◽  
Nonlinear Stress ◽  
Viscoelastic Characteristics ◽  
Water Ratio

When potato tubers had received the exogenic action, water and starch in tubers generated tougor pressure which would act on cell walls in the tuber tissue, so starch content and water ratio have an obvious effect on the mechanical characteristics of potato tubers. In order to provide a mechanical method for detecting the starch content of potato tubers, correlation between viscoelastic characteristics and starch content of tubers was studied. In the research, the tubers of Desiree potato were compressed by cylindrical probe, and showed nonlinear stress-strain curves. The viscoelastic model of potato tuber was established, and its viscoelastic parameters were determined. Meanwhlie, the starch content and water ratio of potato tuber were detected after mechanical tests, and the correlation between viscoelastic parameters and starch content was analysed. According to the results of correlation analysis, viscosity coefficient which had been obtained from the viscoelastic model was significantly correlated with starch content and water ratio. Finally, the regression equation of starch content and the viscosity coefficient was determined.

scholarly journals Simulation of Underground Pipeline Stressed-Deformed State on Sites of Complicated Geological Conditions

10.12737/153 ◽  
2012 ◽  
Vol 1 (6) ◽  
pp. 13-19
Author(s):  
Ларионов ◽  
Valeriy Larionov ◽  
Александров ◽  
Anatoliy Aleksandrov ◽  
Сущев ◽  
...  
Keyword(s):  
Mathematical Model ◽  
Underground Pipeline ◽  
Design Features ◽  
Acceptable Risk ◽  
Geological Conditions ◽  
Deformed State

In estimating the safety of underground pipeline operated in complicated engineering and geological conditions, it is necessary to know and consider the main regularities caused by pipeline interaction with soil. Presented in this article mathematical model of pipeline spatial bend under the action of group of loadings and influences allows estimate influence of complicated geological conditions and design features on pipeline’s stressed-deformed state and reliability.Keywords: acceptable risk, admissible risk, practical expediency principle.

scholarly journals Analytical Study of Soil Displacement Induced by Twin Shield Tunneling in Semi-Infinite Viscoelastic Ground

2020 ◽  
Vol 2020 ◽  
pp. 1-20
Author(s):  
Xin Shi ◽  
Chuanxin Rong ◽  
Houliang Wang ◽  
Linzhao Cui ◽  
Haibing Cai ◽  
...  
Keyword(s):  
Shear Modulus ◽  
Mutual Influence ◽  
Viscoelastic Model ◽  
Three Dimensional ◽  
Viscosity Coefficient ◽  
Shield Tunnel ◽  
Basic Solution ◽  
Shield Tunneling ◽  
Viscoelastic Parameters ◽  
Soil Displacement

Effective measures are needed to strictly control soil displacement caused during the process of shield construction excavation for urban subway tunnels. When calculating the displacement of soil caused by loading or unloading, many previous analytical studies have assumed that the soil was a linear elastic body and ignored the viscosity of the soil. In this study, the Boltzmann viscoelastic model and the Mindlin basic solution were combined to consider the effects of the additional support pressures, the shield shell frictions, the grouting pressures, and the ground loss, and a three-dimensional viscoelastic solution for soil displacement caused by shield tunneling was derived. According to the calculation results of an example, the analytical solution was able to consider the asynchronous construction of the left and right tunnels and the mutual influence of the double shield tunnel. The rationality of the approach proposed in this study was verified by comparing the theoretical solution with the measured settlement values. In addition, the influence of differences in the viscoelastic parameters (the viscosity coefficient, the shear modulus of the elastic element, and the shear modulus of the viscous element) and the geometric parameters (the distance from the excavation surface, the calculated depth, and tunnel spacing) on soil displacement is discussed. The calculation method in this study provides a theoretical basis for predicting the three-dimensional soil deformation caused by shield tunneling, especially in soft clays.

scholarly journals Assessment of the Effect of Inertia Forces in Problems of Underground Pipeline Seismodynamics

2020 ◽  
Vol 9 (3) ◽  
pp. 500-503 ◽  
Keyword(s):  
Life Support ◽  
Experimental Studies ◽  
Seismic Loading ◽  
Seismic Effect ◽  
Underground Pipeline ◽  
Underground Structures ◽  
Calculation Algorithm ◽  
Soil System ◽  
Load Effect ◽  
Inertia Forces

A research to assess the effect of inertia forces in solving specific problems of seismodynamics of underground life support systems is conducted in the paper. A calculation algorithm is constructed using the finite difference method; a system of applied programs based on the developed algorithms and their debugging is created. Dangerous points of maximum normal stress occurrence under seismic loading in underground pipeline are determined taking into account elastic pipe-soil system interaction. The limits of inertial load effect on the behavior of underground systems are estimated. The possibility of considering the seismodynamic problems of underground structures in quasistatic and static statements is substantiated theoretically. The methods of solving the equations of underground pipeline vibrations are given with account for elastic interactions in the pipe-soil system under seismic effect - seismodynamic and quasistatic methods. The conducted computational and experimental studies allow solving the problems of assessing the stress-strain state of pipelines under seismic loading, which is important for practical calculations.

Dislocations in alumina deformed by prismatic slip

1978 ◽  
Vol 36 (1) ◽  
pp. 606-607
Author(s):  
J. Cadoz ◽  
J. Castaing ◽  
J. Philibert
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Basal Slip ◽  
Prismatic Slip ◽  
Compression Tests ◽  
Thin Sections ◽  
Burgers Vector ◽  
Maximum Deformation ◽  
Transmission Electron ◽  
Mechanical Thinning

Plastic deformation of alumina has been much studied; basal slip occurs and dislocation structures have been investigated by transmission electron microscopy (T.E.M.) (1). Non basal slip has been observed (2); the prismatic glide system <1010> {1210} has been obtained by compression tests between 1400°C and 1800°C (3). Dislocations with <0110> burgers vector were identified using a 100 kV microscope(4).We describe the dislocation structures after prismatic slip, using high voltage T.E.M. which gives much information.Compression tests were performed at constant strainrate (∿10-4s-1); the maximum deformation reached was 0.03. Thin sections were cut from specimens deformed at 1450°C, either parallel to the glide plane or perpendicular to the glide direction. After mechanical thinning, foils were produced by ion bombardment. Details on experimental techniques can be obtained through reference (3).

Elastic Interaction Between Modulated Steps on a Vicinal Surface

1995 ◽  
Vol 5 (6) ◽  
pp. 685-698 ◽  
Author(s):  
B. Houchmandzadeh ◽  
C. Misbah
Keyword(s):  
Elastic Interaction ◽  
Vicinal Surface
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