Research on Bursting Behavior in Hydroforming of Double-Cone Tube

2010 ◽  
Vol 154-155 ◽  
pp. 678-685
Author(s):  
Wen Jing Yuan ◽  
Hao Bin Tian ◽  
Xiao Hang Liu ◽  
Xiao Song Wang ◽  
Shi Jian Yuan
Keyword(s):  
Internal Pressure ◽  
Hoop Stress ◽  
Shape Parameter ◽  
Stress Condition ◽  
Axial Stress ◽  
Fem Analysis ◽  
Double Cone ◽  
Thickness Strain ◽  
Arbitrary Length ◽  
Axial Feeding

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.

Thickness Demarcation Circle of Double-Cone Tube during Hydroforming

2011 ◽  
Vol 189-193 ◽  
pp. 2976-2979 ◽  
Author(s):  
Wen Jing Yuan ◽  
Xiao Hang Liu ◽  
Hao Bin Tian ◽  
Xiao Song Wang ◽  
Shi Jian Yuan
Keyword(s):  
Friction Coefficient ◽  
Internal Pressure ◽  
Axial Stress ◽  
Thickness Distribution ◽  
Relative Length ◽  
Fem Analysis ◽  
Mechanical Analysis ◽  
Double Cone ◽  
Relative Thickness ◽  
Feeding Zone

The analytic formula of the thickness demarcation circle during hydroforming of double-cone tube is derived by using the mechanical analysis and the total strain theory. The effect of friction coefficient, expansion coefficient, ratio of axial stress to internal pressure, length of feeding zone, and initial thickness of tube on the thickness distribution can be given by this formula quantitatively, and the analytic results were compared with the FEM analysis and experimental results. The results show that with the increasing of friction coefficient, the ratio of axial stress to internal pressure, the relative length of feeding zone, the distance between thickness demarcation circle and tube end decreased, that means the increasing of length of the thinning zone, and with the increasing of relative thickness of tube blank, the distance between thickness demarcation circle and tube end increased, that means decreasing of length of the thinning zone.

The Assessment of Locally Thinned Areas Subject to a Hoop Stress and an Axial Stress: Background to the Guidance Given in Annex G of BS 7910:2013

2019 ◽  
Author(s):  
Andrew Cosham ◽  
Robert Andrews
Keyword(s):  
Internal Pressure ◽  
Axial Force ◽  
Hoop Stress ◽  
Axial Stress ◽  
Bending Moment ◽  
Full Scale ◽  
Plane Bending

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.

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

2011 ◽  
Vol 130-134 ◽  
pp. 1785-1788 ◽  
Author(s):  
Xiao Hong Li
Keyword(s):  
Internal Pressure ◽  
Hoop Stress ◽  
Axial Stress ◽  
Force Balance ◽  
Static Balance ◽  
Membrane Stress ◽  
Plates And Shells ◽  
The Times ◽  
Region Segment ◽  
Elastic Mechanics

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.

Circumferential Creep Strain of Cylinders Subjected to Internal Pressure: A Comparison of the Theories of Johnson and Bailey

1966 ◽  
Vol 8 (1) ◽  
pp. 22-26 ◽  
Author(s):  
E. C. Larke ◽  
R. J. Parker
Keyword(s):  
Internal Pressure ◽  
Creep Strain ◽  
Wall Thickness ◽  
Circumferential Strain ◽  
Axial Stress ◽  
Integration Procedure ◽  
Graphical Integration ◽  
Simple Equations

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.

Combined-Stress Tests on 24S-T Aluminum-Alloy Tubes

1947 ◽  
Vol 14 (2) ◽  
pp. A147-A153
Author(s):  
W. R. Osgood
Keyword(s):  
Aluminum Alloy ◽  
Hoop Stress ◽  
Axial Stress ◽  
Axial Strain ◽  
Maximum Deviation ◽  
Shearing Stress ◽  
Stress Tests ◽  
Combined Stress ◽  
Stress Strain ◽  
Shearing Strain

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.

Investigation of the Biaxial Behaviour of 316 Stainless Steel Based on Critical Plane Method

2018 ◽  
Vol 774 ◽  
pp. 510-515
Author(s):  
A.S. Cruces ◽  
Pablo Lopez-Crespo ◽  
Belen Moreno ◽  
S. Bressan ◽  
Takamoto Itoh
Keyword(s):  
Stainless Steel ◽  
Hoop Stress ◽  
Axial Stress ◽  
Critical Plane ◽  
316 Stainless Steel ◽  
Dog Bone ◽  
Critical Plane Approach ◽  
Hoop Stresses ◽  
Life Predictions ◽  
Biaxial Behavior

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.

A 1.3 GHz NMR Magnet Design Under High Hoop Stress Condition

2010 ◽  
Vol 20 (3) ◽  
pp. 596-599 ◽  
Author(s):  
A Otsuka ◽  
T Kiyoshi ◽  
M Takeda
Keyword(s):  
Hoop Stress ◽  
Stress Condition ◽  
Magnet Design

ANALYSIS MODEL FOR SHAPE MEMORY EFFECT IN Ti-Ni SYSTEM ALLOY OF RING CONFIGURATION

2006 ◽  
Vol 20 (25n27) ◽  
pp. 3951-3956
Author(s):  
KEISUKE OKITA ◽  
NAGATOSHI OKABE ◽  
TOMOYUKI SATOH ◽  
KAZUNARI UCHIDA
Keyword(s):  
Shape Memory ◽  
Axial Stress ◽  
Volumetric Strain ◽  
Fem Analysis ◽  
Modeling Method ◽  
Test Results ◽  
Analysis Model ◽  
Fem Modeling ◽  
Ring Configuration ◽  
Shape Memory Effects

Shape memory alloys are well known to be used as a ring element for connect coupling two pipes in various fields. In the case of structural and functional designs for a coupling ring of shape memory alloy, we have considered the shape memory effects in multi-axial stress and strain using volumetric strain in each element, so as to make FEM analysis more effective for optimizing the shape and the amount of pre-deformation. Using some uni-axial fundamental test results, as property parameters for FEM, the modeling method simulating the deformation behavior of a coupling ring has been eveloped in order to optimize the configuration and size of a coupling ring. The validity of this FEM modeling method was confirmed by verification experiments.

Effects of Pipe Dimensions and Outer Surface-Buttering Weld Conditions on Residual Stress Distributions

2008 ◽  
Author(s):  
Nobuyoshi Yanagida
Keyword(s):  
Residual Stress ◽  
Residual Stresses ◽  
Outer Surface ◽  
Hoop Stress ◽  
Axial Stress ◽  
Butt Joint ◽  
Stress Distributions ◽  
The Finite Element Method ◽  
Butt Joints ◽  
Inner Surface

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.

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