scholarly journals Influence of the stiffness coefficient of an elastic foundation on the frequency of free oscillations of polyethylene pipes in a semi-underground laying

2019 ◽  
Vol 97 ◽  
pp. 04063
Author(s):  
Vladimir Sokolov ◽  
Igor Razov ◽  
Sviatoslav Volinets
Keyword(s):  
Elastic Medium ◽  
Elastic Foundation ◽  
Cross Section ◽  
Large Diameter ◽  
Stiffness Coefficient ◽  
Mechanical Parameters ◽  
Free Oscillations ◽  
Steel Pipeline ◽  
Polyethylene Pipes ◽  
Thin Walled

The article is about the study of the frequencies of free oscillations of a large-diameter polyethylene gas pipeline with a semi-underground installation, which carried out on the basis of the solution for a semi-underground thin-walled steel pipeline of large diameter. As a result of oscillations, the cross section of the pipeline is deformed, but it strongly depends on the geometrical and mechanical parameters set, for example, on the stiffness coefficient of the elastic medium

scholarly journals Free oscillations of thin-walled bimetallic pipelines of large diameter on an elastic foundation

2018 ◽  
Vol 193 ◽  
pp. 02027
Author(s):  
Vladimir Sokolov ◽  
Igor Razov ◽  
Evgeniy Koynov
Keyword(s):  
Elastic Foundation ◽  
Nuclear Power ◽  
Large Diameter ◽  
Compressive Force ◽  
Free Oscillations ◽  
Working Pressure ◽  
Momentum Theory ◽  
Internal Working ◽  
Nonlinear Version ◽  
Thin Walled

In the article, solutions are obtained for a thin-walled bimetallic pipeline. Solutions are obtained, and the frequencies of free oscillations are investigated taking into account the internal working pressure, the longitudinal compressive force, and the elastic foundation. The solutions were obtained on the basis of a geometrically nonlinear version of the semi-momentum theory of cylindrical shells of the middle bend. The proposed calculations can find application in the nuclear power industry, aviation, and the petrochemical industry.

scholarly journals Free oscillations of thin-walled bimetallic pipelines of large diameter on an elastic foundation

2018 ◽  
Vol 239 ◽  
pp. 06008
Author(s):  
Vladimir Sokolov ◽  
Igor Razov ◽  
Evgeniy Koynov
Keyword(s):  
Elastic Foundation ◽  
Nuclear Power ◽  
Large Diameter ◽  
Compressive Force ◽  
Free Oscillations ◽  
Working Pressure ◽  
Momentum Theory ◽  
Internal Working ◽  
Nonlinear Version ◽  
Thin Walled

In the paper, solutions for a thin-walled bimetallic pipeline are obtained. The frequencies of free oscillations are investigated, taking into account the internal working pressure, the longitudinal compressive force, and the elastic foundation. The solutions were obtained on the basis of a geometrically nonlinear version of the semi-momentum theory of cylindrical shells of the middle bend. The proposed calculations can be used in the nuclear power industry, aviation, and petrochemical industry.

scholarly journals Investigation of the frequencies of free oscillations of the above-ground main pipelines depending on the type of fastening

2018 ◽  
Vol 193 ◽  
pp. 02033
Author(s):  
Vladimir Sokolov ◽  
Igor Razov ◽  
Evgeniy Koinov ◽  
Alexander Korkishko
Keyword(s):  
Large Diameter ◽  
Compressive Force ◽  
Gas Pipeline ◽  
Free Oscillations ◽  
Bending Vibrations ◽  
Working Pressure ◽  
Internal Working ◽  
Main Pipelines ◽  
Thin Walled ◽  
Free Bending

In this paper, we solve the problem of free bending vibrations of a thin-walled gas pipeline of large diameter laid above the ground on supports. The gas pipeline is considered as a cylindrical shell subject to the action of a stationary internal working pressure, the parameter of the longitudinal compressive force. The frequencies of free oscillations and the influence of parameters on the gas pipeline are compared with different versions of the supports.

scholarly journals A study of the length parameter and the longitudinal compressive forces in the determination of frequencies of free vibrations of thin-walled underground pipelines of large diameter

2019 ◽  
Vol 6 (3) ◽  
Author(s):  
Andrey Dmitriev ◽  
Vladimir Sokolov ◽  
Aleksey Bereznev
Keyword(s):  
Cross Section ◽  
Shell Theory ◽  
Natural Frequencies ◽  
Large Diameter ◽  
Pressure Coefficient ◽  
Critical Force ◽  
The Core ◽  
Underground Pipelines ◽  
Thin Walled ◽  
The Cross

Earlier work on the study of frequency characteristics of thin-walled underground pipeline to obtain an equation for finding the natural frequencies of the straight sections of the pipeline, taking into account the parameter of the longitudinal force, the magnitude of internal pressure, coefficient of elastic resistance of the soil, the option of thin tubing and added mass of the soil. In this article, using the obtained equation, we study the influence of the length of the section of the pipeline laid in the soil with different physical-mechanical characteristics, and the effect of the parameter of the longitudinal compressive forces at the frequency of free oscillations of thin-walled straight pipeline under the action of various internal working pressure for pipes of different diameters with different wall thicknesses. On the basis of the design data defined in the derived formulae, is determined by the criterion of application of shell theory or the core theory for finding the natural frequencies of thin-walled underground pipelines of large diameter, depending on the length of the element. Simultaneously, the obtained expression allows to determine the critical force at which buckling occurs in the core of the theory («beam buckling»), as well as the formula to determine the critical force, from which buckling occurs by shell theory (flattening of the cross section). Based on these data, it is concluded that flattening the cross section of the pipeline will occur when the force is at times less than required for the formation of «arch release», and consequently to ensure the reliability of underground thin-walled large diameter pipeline should be the first thing to check for resistance on the shell theory.

Analysis of Efficiency of Drilling of Large-Diameter Wells With a Profiled Wing Bit / Badania Efektywności Wiercenia Studni Wielkośrednicowych Świdrem Skrawającym z Profilowanymi Skrzydłami

2012 ◽  
Vol 57 (2) ◽  
pp. 363-373
Author(s):  
Jan Macuda
Keyword(s):  
Average Rate ◽  
Large Diameter ◽  
Open Pit ◽  
Mechanical Parameters ◽  
Drilling Rate ◽  
Geological Conditions ◽  
Rock Drillability ◽  
Drilling Technology ◽  
Weight On Bit ◽  
Rotary Speed

Abstract In Poland all lignite mines are dewatered with the use of large-diameter wells. Drilling of such wells is inefficient owing to the presence of loose Quaternary and Tertiary material and considerable dewatering of rock mass within the open pit area. Difficult geological conditions significantly elongate the time in which large-diameter dewatering wells are drilled, and various drilling complications and break-downs related to the caving may occur. Obtaining higher drilling rates in large-diameter wells can be achieved only when new cutter bits designs are worked out and rock drillability tests performed for optimum mechanical parameters of drilling technology. Those tests were performed for a bit ø 1.16 m in separated macroscopically homogeneous layers of similar drillability. Depending on the designed thickness of the drilled layer, there were determined measurement sections from 0.2 to 1.0 m long, and each of the sections was drilled at constant rotary speed and weight on bit values. Prior to drillability tests, accounting for the technical characteristic of the rig and strength of the string and the cutter bit, there were established limitations for mechanical parameters of drilling technology: P ∈ (Pmin; Pmax) n ∈ (nmin; nmax) where: Pmin; Pmax - lowest and highest values of weight on bit, nmin; nmax - lowest and highest values of rotary speed of bit, For finding the dependence of the rate of penetration on weight on bit and rotary speed of bit various regression models have been analyzed. The most satisfactory results were obtained for the exponential model illustrating the influence of weight on bit and rotary speed of bit on drilling rate. The regression coefficients and statistical parameters prove the good fit of the model to measurement data, presented in tables 4-6. The average drilling rate for a cutter bit with profiled wings has been described with the form: Vśr= Z ·Pa· nb where: Vśr- average drilling rate, Z - drillability coefficient, P - weight on bit, n - rotary speed of bit, a - coefficient of influence of weight on bit on drilling rate, b - coefficient of influence of rotary speed of bit on drilling rate. Industrial tests were performed for assessing the efficiency of drilling of large-diameter wells with a cutter bit having profiled wings ø 1.16 m according to elaborated model of average rate of drilling. The obtained values of average rate of drilling during industrial tests ranged from 8.33×10-4 to 1.94×10-3 m/s and were higher than the ones obtained so far, i.e. from 181.21 to 262.11%.

First and Second Order Elastoplastic Analyses of Thin-Walled Metal Members using Generalized Beam Theory

2018 ◽  
Author(s):  
Miguel Abambres
Keyword(s):  
Finite Element ◽  
Stainless Steel ◽  
Cross Section ◽  
Beam Theory ◽  
Second Order ◽  
Flow Rule ◽  
Non Linear ◽  
Thin Walled ◽  
Shell Finite Element ◽  
Generalized Beam Theory

Original Generalized Beam Theory (GBT) formulations for elastoplastic first and second order (postbuckling) analyses of thin-walled members are proposed, based on the J2 theory with associated flow rule, and valid for (i) arbitrary residual stress and geometric imperfection distributions, (ii) non-linear isotropic materials (e.g., carbon/stainless steel), and (iii) arbitrary deformation patterns (e.g., global, local, distortional, shear). The cross-section analysis is based on the formulation by Silva (2013), but adopts five types of nodal degrees of freedom (d.o.f.) – one of them (warping rotation) is an innovation of present work and allows the use of cubic polynomials (instead of linear functions) to approximate the warping profiles in each sub-plate. The formulations are validated by presenting various illustrative examples involving beams and columns characterized by several cross-section types (open, closed, (un) branched), materials (bi-linear or non-linear – e.g., stainless steel) and boundary conditions. The GBT results (equilibrium paths, stress/displacement distributions and collapse mechanisms) are validated by comparison with those obtained from shell finite element analyses. It is observed that the results are globally very similar with only 9% and 21% (1st and 2nd order) of the d.o.f. numbers required by the shell finite element models. Moreover, the GBT unique modal nature is highlighted by means of modal participation diagrams and amplitude functions, as well as analyses based on different deformation mode sets, providing an in-depth insight on the member behavioural mechanics in both elastic and inelastic regimes.

Sign in / Sign up

Export Citation Format

Share Document