Hoop Membrane Stress Analysis of Elbow-Pipe under Single Internal Pressure

2011 ◽  
Vol 130-134 ◽  
pp. 1785-1788 ◽  
Author(s):  
Xiao Hong Li

In the article, a kind of regional force balance method based on plates and shells theories of elastic mechanics are applied to study the hoop membrane stress of the elbow-pipe, while internal pressure is as a single load. By learning the static balance equation ΣFx=0 of a micro-region segment of pipe shell, it is found that axial membrane stress σ1 is perpendicular to x-direction and has no effect to equilibrium condition, here axial stress σ1is discussed explicitly. It shows that, the hoop membrane stress σh of the elbow is the times of straight tube’s hoop stress.

Author(s):  
Andrew Cosham ◽  
Robert Andrews

Abstract Annex G Assessment of locally thinned areas (LTAs) in BS 7910:2013 is applicable to LTAs in cylinder, a bend and a sphere or vessel end. It can be used to assess the longitudinally-orientated LTA in a cylinder subject to a hoop stress and a circumferentially-orientated LTA in a cylinder subject to an axial stress (due to axial force, in-plane bending moment and internal pressure), and also to assess an LTA subject to a hoop stress and an axial stress. An outline of the origins of Annex G is given. A comparison with full-scale burst tests of pipes or vessels containing LTAs subject to a hoop stress and an axial stress is presented. It is demonstrated that the method in G.4.3 Hoop stress and axial stress is conservative.


2010 ◽  
Vol 154-155 ◽  
pp. 678-685
Author(s):  
Wen Jing Yuan ◽  
Hao Bin Tian ◽  
Xiao Hang Liu ◽  
Xiao Song Wang ◽  
Shi Jian Yuan

Firstly, the geometry condition of useful wrinkles during the hydroforming of double-cone tube was given. Then the stress condition of useful wrinkles was given by formula between the parameters of wrinkles shape at the end of axial feeding and internal pressure, hoop stress and axial stress. The analytical results were compared with the FEM analysis and experiments results. The results show that the useful wrinkles must meet both the geometry condition and the stress condition. The geometry condition of useful wrinkles is that the area of arbitrary length of wrinkles is a little smaller than the area of corresponding die cavity. The stress condition of useful wrinkles is that shape parameter G is not smaller than the radius R at the top of middle wrinkle. That means the increment of thickness strain dεt is positive and no thickness thinning will occur during the calibration. When the wrinkles didn’t match geometry condition, the dead wrinkles or bursting will take place. And when the wrinkles didn’t match stress condition, the bursting at top of middle wrinkle will occur during the calibration.


1966 ◽  
Vol 8 (1) ◽  
pp. 22-26 ◽  
Author(s):  
E. C. Larke ◽  
R. J. Parker

When considering the creep of cylinders subjected to internal pressure, the theory of Johnson et al. takes into account progressive changes of radial, circumferential and axial stress at any point in the wall thickness. This approach differs from that put forward by Bailey, who assumed that these stresses remained constant with time. The present paper summarizes an examination of both theories, with particular reference to outside and bore diameters, and presents simple equations which enable circumferential strain to be calculated without using the complex graphical integration procedure suggested by Johnson. Furthermore, it is demonstrated that these equations are mathematically identical with those derived by Bailey.


1947 ◽  
Vol 14 (2) ◽  
pp. A147-A153
Author(s):  
W. R. Osgood

Abstract Combined-stress tests were made on five 24S-T aluminum-alloy tubes, 1 3/4 in. ID × 0.05 in. thick. The ratios of circumferential (hoop) stress to axial stress were 0, 1/2, 1, 2, and ∞. The tubes were tested to failure and sufficient measurements of circumferential strain and axial strain were taken to plot stress-strain curves almost up to rupture. The results are presented in the form of two sets of stress-strain curves for each ratio of stresses, namely, maximum shearing stress plotted against maximum shearing strain, and octahedral shearing stress plotted against octahedral shearing strain. In each plot the maximum deviation of the curves is about ± 5 per cent. A method of evaluating small octahedral shearing strains from the data is given which does not assume Poisson’s ratio to be 1/2.


2018 ◽  
Vol 774 ◽  
pp. 510-515
Author(s):  
A.S. Cruces ◽  
Pablo Lopez-Crespo ◽  
Belen Moreno ◽  
S. Bressan ◽  
Takamoto Itoh

In this work the biaxial behavior of 316 stainless steel is studied under the lens of critical plane approach. A series of ten experiments were developed on dog bone shape hollow cylindrical specimens made of type 316 stainless steel. Five different loading conditions were assessed, with (i) only axial stress, (ii) only hoop stress, (iii) proportional combination of axial and hoop stresses, (iv) non-proportional combination of axial and hoop stresses with square shape and (v) non-proportional combination of axial and hoop stresses with L-shape. The fatigue analysis is performed following four different critical plane theories, namely Wang-Brown, Fatemi-Socie, Liu I and Liu II. The efficiency of all four theories is studied in terms of the accuracy of their life predictions.


Author(s):  
Nobuyoshi Yanagida

Effects of pipe dimensions and outer surface-buttering weld conditions on residual stress distributions were evaluated using the finite element method. Residual stresses were analyzed for 508–mm-diameter (500A) pipe 38.1 mm thick, 508–mm-diameter (500A) pipe 15.1 mm thick, and 267–mm-diameter (250A) pipe 15.1 mm thick. After the residual stresses at pipe butt joints were analyzed, residual stresses at these joints subjected to the outer surface-buttering welds were analyzed. Residual stresses were determined for various weld widths, thicknesses, and heat inputs. These analyses indicate that tensile axial stress occurred at inner surface of the pipe butt joint and that it decreased with increasing the outer surface buttering-weld width or heat input. They also indicate that compressive hoop stress occurred at inner surface of the joint and that outer surface-buttering weld increased it. The outer surface-buttering weld conditions that generate compressive residual stress at the inner surface of the pipe butt joints were determined.


Author(s):  
Robert B. Francini ◽  
Jacob D. Wahl ◽  
Nolan T. Quade

The casings in a gas storage or production well can have large longitudinal loads in addition to the hoop stress resulting from internal pressure. Under certain circumstances these loads need to be taken into account when evaluating the remaining strength of corroded areas. The most commonly used method for corrosion evaluation is based on B31G which does not include longitudinal loads. This paper outlines the range of longitudinal loading where the B31G approach is valid. In addition, it presents a method to evaluate the remaining strength of the corroded area where the B31G approach is not valid. The procedure has been validated by burst tests of casing with real and machined metal loss under axial loading.


Author(s):  
G. Shen ◽  
W. R. Tyson

A stress-strain equation of Ramberg-Osgood type is proposed to correlate the longitudinal stress with longitudinal strain of a thin plate when a constant stress is applied transversely. The same approach can be used to correlate the axial stress with axial strain for a thin-walled pipe in axial tension with internal pressure. The proposed stress-strain equation relating the longitudinal stress and strain closely approximates that of deformation theory. The effect of a secondary stress (hoop stress) on the J-integral for a circumferential crack in a pipe under axial load and internal pressure is evaluated by finite element analysis (FEA). The results show that the J-integral decreases with internal pressure at a given axial stress but increases with internal pressure at a given axial strain. It is concluded that while a secondary stress may be safely neglected in a stress-based format because it decreases the driving force at a given applied stress, it should not be neglected in a strain-based format because it significantly increases the driving force at a given applied strain.


2012 ◽  
Vol 189 ◽  
pp. 239-244
Author(s):  
Deng Wang Wang ◽  
Xue Jun Qin ◽  
Shi Ying Tang ◽  
Wen Xiang Liu ◽  
Hui Wang

Broken rules of cylindrical steel shell subjected to internal blast loads is the foundation for conducting safety assessment and failure analysis of explosion containment vessels. The experiments were carried out broken rules of the cylindrical steel shells subjected to internal blast loadings at the centers. The elastic-plastic response of cylindrical steel shells was conducted using nonlinear dynamic finite element analysis code LS-DYNA. The results show that the deformation was’t a discrepancy in the explosion center of the cylindrical steel shell in same space, and the deformation descended slower along with thickness augmentation in the end of explosion center. The radial stress、hoop stress and axial stress was a discrepancy in the thickness way of cylindrical steel shell of explosion center The most leading cause of destructivity of cylindrical steel shell was that inner wall bearing normal stress and exterior wall bearing tensile stress; the hoop stress was broken more than axial stress cylindrical steel shell. The whole process was presenting hoop fractured and axial growth.


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