The Application of Long and Short Cylindrical Shell Solutions for Stress and Flexibility Determination in a Single Mitred Bend

2016 ◽  
Author(s):  
Igor Orynyak ◽  
Andrii Bogdan ◽  
Iryna Selivestrova
Keyword(s):  
Cylindrical Shell ◽  
Shell Theory ◽  
Bending Moment ◽  
Axial Direction ◽  
Piping System ◽  
Structural Elements ◽  
Thin Cylindrical Shell ◽  
Straight Pipe ◽  
Pipe Bend ◽  
Short Shell

The continuous pipe bend behavior is well elaborated in literature. It is characterized by local ovalization of each cross section during bending which results in enhanced flexibility of it as compared to straight pipe. When pipe bend approaches some other structural elements of a piping system the end effect take place which can be described by so called long shell solution. This long solution is, in fact, a semi-membrane Vlasov’s solution when the derivative of any geometrical or force function in axial direction is much smaller than in the circumferential one [1]. Mitred bend is formed by conjunction by welding of two oblique sections of initially straight pipes. Its behavior during loading by pressure or bending moment is not evident and poorly described in standards. The goal of this paper is to give a set of general functions within a thin cylindrical shell theory which will give the opportunity to consider the mitred bend as an element of a piping system. Here we additionally introduce the so called short solution when the derivative of any parameter in axial direction is much bigger than that in circumferential one. Its main goal is to give the local behavior of stress in the vicinity of the oblique weld. Each of these two solutions satisfy by differential equations of forth order. The complete theoretical solution for a particular mitred bend is compared with a) existing analytical solutions and formulas; b) numerical results obtained by FEM with distinction of the zones of influence of a long as well as short shell solution; c) experimental data on real mitred bends given in the literature.

Local loads on a toroidal shell

1992 ◽  
Vol 27 (2) ◽  
pp. 59-66 ◽  
Author(s):  
D Redekop ◽  
F Zhang
Keyword(s):  
Cylindrical Shell ◽  
Shell Theory ◽  
Elastic Shell ◽  
Toroidal Shell ◽  
Pipe Bend ◽  
Local Loads ◽  
Simply Supported ◽  
Linear Elastic ◽  
Wide Range ◽  
Theory Solution

In this study the effect of local loads applied on a sectorial toroidal shell (pipe bend) is considered. A linear elastic shell theory solution for local loads is first outlined. The solution corresponds to the case of a shell simply supported at the two ends. Detailed displacement and stress results are then given for a specific shell with loadings centred at three positions; the crown circles, the extrados, and the intrados. These results are compared with results for a corresponding cylindrical shell. The paper concludes with a table summarizing results for characteristic displacements and stresses in a number of shells, covering a wide range of geometric parameters.

Effect of Bend Angle on Gross Plastic Deformation of Pipe Bends: A Finite Element Based Study

2015 ◽  
Author(s):  
Anindya Bhattacharya ◽  
Sachin Bapat ◽  
Hardik Patel ◽  
Shailan Patel
Keyword(s):  
Plastic Deformation ◽  
Finite Element ◽  
Failure Mechanisms ◽  
Bending Moment ◽  
Bend Angle ◽  
Piping System ◽  
Plastic Collapse ◽  
Collapse Load ◽  
Pipe Bend ◽  
Bend Angles

Bends are an integral part of a piping system. Because of the ability to ovalize and warp they offer more flexibility when compared to straight pipes. Piping Code ASME B31.3 [1] provides flexibility factors and stress intensification factors for the pipe bends. Like any other piping component, one of the failure mechanisms of a pipe bend is gross plastic deformation. In this paper, plastic collapse load of pipe bends have been analyzed for various bend parameters (bend parameter = tRbrm2) under internal pressure and in-plane bending moment for various bend angles using both small and large deformation theories. FE code ABAQUS version 6.9EF-1 has been used for the analyses.

Quantification of Arterial Stiffness Reduced Effect of Vessel Geometry

2008 ◽  
Author(s):  
Shinichiro Ota ◽  
Toshitaka Yasuda ◽  
Takashi Saito
Keyword(s):  
Mechanical Properties ◽  
Cylindrical Shell ◽  
Arterial Stiffness ◽  
Wall Thickness ◽  
Shell Theory ◽  
Dynamic Strain ◽  
Thin Cylindrical Shell ◽  
Inner Pressure ◽  
Latex Tube ◽  
Mechanical Factors

Arteriosclerosis is such as phenomena hardening of arteries, with thickening and loss of elasticity. Previous indexes include effect of geometric and mechanical factors as the radius, the wall thickness and mechanical properties of arteries. In this study, we proposed viscoelasticity indexes formulated by thin cylindrical shell theory estimated dynamic strain, and this index was independent of wall thickness and radius of arterial vessels. To confirm the validity of these indexes, we evaluated the parameters of viscoelasticity using the latex tube with different wall thickness of blood vessel model. We measured a radius of the latex tube and an inner pressure maintained by a pulsatile pump in a mock circuit filled with the water. Estimating the parameters of elasticity using these measured values, we concluded that a proposal index was independent of the wall thickness of the artery.

Non-Axisymmetric Dynamic Response of Imperfectly Bonded Buried Orthotropic Thin Empty Cylindrical Shell Due to Incident Shear Wave (SH Wave)

2011 ◽  
Vol 2 (2) ◽  
pp. 40-56
Author(s):  
Rakesh Singh Rajput ◽  
Sunil Kumar ◽  
Alok Chaubey ◽  
J. P. Dwivedi
Keyword(s):  
Cylindrical Shell ◽  
Dynamic Response ◽  
Shear Wave ◽  
Shell Theory ◽  
Surrounding Medium ◽  
Sh Wave ◽  
Thin Cylindrical Shell ◽  
Sh Waves ◽  
Stiffness And Damping ◽  
Thin Shell Theory

Non-axisymmetric dynamic response of imperfectly bonded buried orthotropic thin empty pipelines subjected to incident shear wave (SH-wave) is presented here. In the thin shell theory the effect of shear deformation and rotary inertia is not considered. The pipeline has been modeled as an infinite thin cylindrical shell imperfectly bonded to surrounding. A thin layer is assumed between the shell and the surrounding medium (soil) such that this layer possesses the properties of stiffness and damping both. The degree of imperfection of the bond is varied by changing the stiffness and the damping parameters of this layer. Although a general formulation including P-, SV-, and SH-wave excitations are presented, numerical results are given for the case of incident SH-waves only. Comparison of axisymmetric and non-axisymmetric responses are also furnished.

Buckling of Thin Cylindrical Shell Under Hoop Stresses Varying in Axial Direction

1957 ◽  
Vol 24 (3) ◽  
pp. 405-412
Author(s):  
N. J. Hoff
Keyword(s):  
Cylindrical Shell ◽  
Thermal Stresses ◽  
Axial Direction ◽  
Elastic Buckling ◽  
Thin Cylindrical Shell ◽  
Simply Supported ◽  
Buckling Stress ◽  
Compressive Stresses ◽  
Hoop Stresses ◽  
Approximate Formulas

Abstract The buckling of a thin cylindrical shell simply supported along the perimeter of its end sections is analyzed under hoop compressive stresses varying in the axial direction. The thermal stresses arising from a uniform increase in the temperature of the cylinder are determined. It is found that such thermal stresses are not likely to cause elastic buckling. Simple approximate formulas are developed for buckling stress and thermal stress.

Axial Leakage Flow-Induced Vibration of a Thin Cylindrical Shell With Respect to Lateral Vibration

2003 ◽  
Vol 125 (2) ◽  
pp. 158-164 ◽  
Author(s):  
Katsuhisa Fujita ◽  
Atsuhiko Shintani ◽  
Masakazu Ono
Keyword(s):  
Cylindrical Shell ◽  
Shell Theory ◽  
Beam Theory ◽  
Navier Stokes ◽  
Leakage Flow ◽  
Lateral Vibration ◽  
Thin Cylindrical Shell ◽  
Flow Induced Vibration ◽  
Navier Stokes Equation ◽  
Coupled Equations

In this paper, the stability of a thin cylindrical shell subjected to axial leakage flow is discussed. In this paper, the second part of a study of the axial leakage flow-induced vibration of a thin cylindrical shell, we focus on lateral vibration, that is, the beamlike vibration of a shell. The coupled equations between a shell and a fluid are obtained by using the Donnell’s shell theory and the Navier-Stokes equation as same as the former paper. The influence of the axial velocity on the unstable vibration phenomena is clarified concerning the beamlike vibration mode of a shell. The numerical results on shell theory are compared with the ones on beam theory which have been already reported by the authors; and the numerical parameter studies are done for various dimensions of a shell and a fluid.

259 Research on a lug tire model based on thin cylindrical shell theory

2009 ◽  
Vol 2009 (0) ◽  
pp. _259-1_-_259-5_
Author(s):  
Yuya FUKUDA ◽  
Katsuhide FUJITA ◽  
Mitsugu KANEKO ◽  
Takashi SAITO
Keyword(s):  
Cylindrical Shell ◽  
Shell Theory ◽  
Tire Model ◽  
Thin Cylindrical Shell ◽  
Model Based

Effect of Bend Angle on Gross Plastic Deformation of Pipe Bends for Out-of-Plane Bending: A Study Using Plastic Work Curvature Method

2016 ◽  
Author(s):  
Anindya Bhattacharya ◽  
Sachin Bapat ◽  
Hardik Patel ◽  
Shailan Patel ◽  
Michael P. Cross
Keyword(s):  
Plastic Deformation ◽  
Internal Pressure ◽  
Bending Moment ◽  
Plastic Work ◽  
Bend Angle ◽  
Piping System ◽  
Plastic Collapse ◽  
Pipe Bend ◽  
Out Of Plane ◽  
Plane Bending

Bends are an integral part of a piping system. Because of the ability to ovalize and warp they offer more flexibility when compared to straight pipes. Piping Code ASME B31.3 [1] provides flexibility factors and stress intensification factors for pipe bends. Like any other piping component, one of the failure mechanisms of a pipe bend is gross plastic deformation. In this paper, plastic collapse load of pipe bends have been analyzed for various bend parameters (bend parameter = tRbrm2) under internal pressure and out-of-plane bending moment for various bend angles using both small and large deformation theories. FE code ABAQUS version 6.9EF-1 has been used for the analyses. The goal of the paper is to develop an expression for plastic collapse moment for a bend using plastic work curvature method when the bend is subjected to out-of-plane bending moment and internal pressure as a function of bend angle and bend parameter.

Deformation of a Pipe Bend as an Element of a Piping System Under Harmonic Loading

2013 ◽  
Author(s):  
Anatolii Batura ◽  
Igor Orynyak ◽  
Sergii Radchenko ◽  
Mykhaylo Borodii
Keyword(s):  
Shell Theory ◽  
High Accuracy ◽  
Piping System ◽  
Dynamic Coefficient ◽  
Harmonic Loading ◽  
Pipe Bend ◽  
Analytical Expression ◽  
Harmonic Vibrations ◽  
Shell Models ◽  
Original Approach

Analysis of the vibration behavior of a pipe bend was conducted by the methods of the shell theory. To take into account with a high accuracy the ovalization of this piping element under harmonic vibrations authors proposed to use an analytical expression for the dynamic coefficient of the bend flexibility, which is the analog of well-known static Karman’s coefficient. This original approach allows to use beam models instead of the complex shell models for rigorous pipeline modeling.

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