Formation of residual stresses during frontal hardening of spherical specimen with allowance for internal pressure

1985 ◽  
Vol 21 (3) ◽  
pp. 336-340
Author(s):  
L. V. Klychnikov ◽  
S. P. Davtyan ◽  
N. A. Belyaeva ◽  
S. I. Khudyaev ◽  
N. S. Enikolopyan
Keyword(s):  
Residual Stresses ◽  
Internal Pressure ◽  
Frontal Hardening

Experimental and Analytical Leak Characterization for Axial Through-Wall Cracks in a Liquids Pipeline

2014 ◽  
Author(s):  
Mohamed R. Chebaro ◽  
Nader Yoosef-Ghodsi ◽  
David M. Norfleet ◽  
Jason H. Bergman ◽  
Aaron C. Sutton
Keyword(s):  
Residual Stress ◽  
Residual Stresses ◽  
Internal Pressure ◽  
Crack Opening ◽  
Full Scale ◽  
Leak Rate ◽  
Propagation Mechanism ◽  
Element Analysis ◽  
Fea Model ◽  
Experimental Findings

Three pipeline sections containing defects of interest were non-destructively tested in the field, cut out and shipped to a structural laboratory to undergo full-scale testing. The common objectives of the experiments were to determine (1) the leak initiation pressure and (2) the leak rate at various specified internal pressures. While two spools (Specimens A and B) contained through-wall cracks, the third (Specimen C) had a partial through-wall crack with similar characteristics. The capacity of through-wall defects to withstand a level of internal pressure without leaking is due to the resultant local, compressive hoop residual stresses. Specimen C underwent full-scale pressure cycling to further comprehend the crack propagation mechanism in order to correlate it to field operation and analytical fatigue life predictions. To enhance the understanding of the physical crack behaviour as a function of internal pressure, a comprehensive finite element analysis (FEA) model was built using SIMULIA’s Abaqus software. The model inputs incorporated results from the above-mentioned laboratory tests, in addition to extensive radial, circumferential and axial residual stress measurements using the X-ray diffraction (XRD) technique, obtained on three pipe spools cut out from the same line. The resulting crack opening parameters from FEA were input into a closed-form fluid mechanics (FM) model, which was calibrated against a computational fluid dynamics (CFD) model, to determine the corresponding leak initiation pressures and leak rates. These outcomes were then compared to experimental findings. The FEA and FM models were subsequently employed to carry out a parametric study for plausible combinations of feature geometries, material properties, operational pressures and residual stresses to replicate field conditions. The key outcome from this study is the experimental and analytical demonstration that, for given fluid properties and pressures, the leak threshold and leak rate for through-wall cracks are primarily dependent upon the crack geometry and local residual stress distributions.

Effect of a nonuniform temperature field on the distribution of the residual stresses with frontal hardening

1980 ◽  
Vol 16 (3) ◽  
pp. 368-372 ◽  
Author(s):  
L. V. Klychnikov ◽  
S. P. Davtyan ◽  
S. I. Khudyaev ◽  
N. S. Enikolopyan
Keyword(s):  
Temperature Field ◽  
Residual Stresses ◽  
Nonuniform Temperature ◽  
Nonuniform Temperature Field ◽  
Frontal Hardening

Stress Analysis of O.D. Notched Thick-Walled Cylinders Subjected to Internal Pressure or Thermal Loads

1981 ◽  
Vol 103 (1) ◽  
pp. 76-84 ◽  
Author(s):  
J. A. Kapp ◽  
G. A. Pflegl
Keyword(s):  
Stress Concentration ◽  
Residual Stresses ◽  
Internal Pressure ◽  
Stress Analysis ◽  
Stress Concentration Factor ◽  
Concentration Factor ◽  
Maximum Stress ◽  
Additional Result ◽  
Finite Element Stress Analysis ◽  
Temperature Loads

Finite element stress analysis has been performed to determine the effects of two O.D. notch configurations in a cylinder subjected to internal pressure, or containing autofrettage residual stress. The effects on the residual stresses were determined by simulating these stresses with equivilent temperature loads. The results show that the deeper of the two notch cofigurations is far more severe resulting in a maximum stress concentration factor of 6.6. The shallower notch has a maximum stress concentration factor of 3.7. An additional result is that by introducing notches in autofrettaged cylinders a significant amount of the residual stresses are relieved which indicates that smaller applied pressures can be applied before yielding occurs. The results also show that the possibility of O.D. initiated fatigue failure is greatly increased.

scholarly journals Creep of Thick-Walled Cylinders under Internal Pressure at High Temperature, and Measurement of Residual Stresses

1964 ◽  
Vol 13 (126) ◽  
pp. 163-168 ◽  
Author(s):  
Shuji TAIRA ◽  
Ryoichi KOTERAZAWA ◽  
Ryuichi OHTANI
Keyword(s):  
High Temperature ◽  
Residual Stresses ◽  
Internal Pressure

Residual Stress Estimation and Shakedown Evaluation Using GLOSS Analysis

1994 ◽  
Vol 116 (3) ◽  
pp. 290-294 ◽  
Author(s):  
R. Seshadri
Keyword(s):  
Residual Stress ◽  
Stress Intensity ◽  
Residual Stresses ◽  
Internal Pressure ◽  
Assessment Method ◽  
Simple Method ◽  
Stress Estimation ◽  
Walled Cylinder

A simple method for estimating residual stresses using the GLOSS analysis is presented, and a shakedown assessment method is proposed. Practical pressure components exhibit some local elastic follow-up, and thereby induce smaller residual stresses than implied by uniaxial models. In this context, the effectiveness of “autofrettaging” is examined by studying a thick-walled cylinder subjected to an internal pressure. Modifications to the P + Q stress-intensity limit are suggested, and compared with Roche’s criterion. The method presented here is useful for configurations experiencing small to medium amounts of follow-up, which covers many practical situations.

Investigation of Hydrostatic Pressure Effect on the Residual Stresses of Circumferentially Butt-Welded Steel Pipes

2012 ◽  
Vol 134 (3) ◽  
Author(s):  
M. Foroutan ◽  
M. E. Aalami-Aleagha ◽  
S. Feli ◽  
S. Nikabadi
Keyword(s):  
Structural Analysis ◽  
Residual Stresses ◽  
Internal Pressure ◽  
Transfer Problem ◽  
Three Dimensional ◽  
Welding Process ◽  
Heat Power ◽  
Welded Steel ◽  
Spherical Domain ◽  
Steel Pipes

In this paper, the effect of hydrostatic testing internal pressure on the residual stresses of circumferentially butt-welded steel pipes is investigated by a three dimensional finite elements simulation based on ansys11 code. Residual stresses due to welding process are calculated by an uncoupled analysis. In this analysis, at first, a transient heat transfer problem is solved. Output of this analysis is temperature distribution history .This output is used as the structural analysis load. Output of structural analysis is welding residual stresses. The most important part of such simulations is modeling of heat power source. In the present work, heat power of welding electrode is simulated by a moving heat source with Gaussian distribution on a spherical domain. The presented model is used for calculation of residual stresses in an 8 in. three pass butt-welded steel pipe. Finally, the effects of hydrostatic testing internal pressure on the residual stresses are studied by the proposed model. The results obtained from this study show that the hydrostatic testing pressure has a significant effect on residual stresses.

scholarly journals The Influence of Thermomechanical Coupling on the Behaviour of Athick-Walled Metallic Tube Subjected to Internal Pressure

2018 ◽  
Vol 23 (3) ◽  
pp. 751-766
Author(s):  
Z. Śloderbach
Keyword(s):  
Plastic Deformation ◽  
Heat Flow ◽  
Residual Stresses ◽  
Internal Pressure ◽  
Coupling Effect ◽  
Applied Pressure ◽  
Thermomechanical Coupling ◽  
Stored Energy ◽  
Adiabatic Processes ◽  
Elastic Unloading

Abstract In this study, the influence of thermomechanical coupling effect - the effect of thermal expansion due to dissipation of the energy of plastic deformation, with and without taking into account the stored energy of plastic deformation (SEPD) for the distribution of stresses, strains, temperature, the applied pressure and the residual stresses is examined. The residual stresses remain in a thick-walled tube (a cylindrical thick-walled tank) after removing the internal pressure in the process of purely elastic unloading. The analysis is made on the example of an analitycal solution for a thick-walled tube subjected to a quasistatically increasing internal pressure for the case of adiabatic processes (without heat flow). Since the loading with internal pressure is quasi-static (monotonic), then neglecting the process of heat flow can lead to some different results in calculated stresses, deformations, temperature, internal pressure and residual stresses. The calculations for isothermal type of processes of deformations (without heat or ideal cooling) are also performed for the estimation of these differences. The results calculated for the process with heat flow should be intermediate between the values obtained for isothermal and adiabatic processes.

Analysis of Residual Stress around Semi-Circular Surface Notches due to Excessive Pressure

2017 ◽  
Vol 754 ◽  
pp. 123-126 ◽  
Author(s):  
Takuichiro Ino ◽  
Yohei Sonobe ◽  
Akihide Saimoto ◽  
Tomokazu Hashiguchi
Keyword(s):  
Residual Stresses ◽  
Internal Pressure ◽  
Mechanical Characteristics ◽  
Body Force ◽  
Process Zone ◽  
Wave Length ◽  
Stress Fields ◽  
Excessive Pressure ◽  
Body Force Method ◽  
Circular Surface

Residual stresses due to excessive internal pressure applied to an array of semi-circular surface notches is analyzed by body force method. The treated problem corresponds to a simple model of the Stealth Dicing (SD) which is expected as an alternative splitting technology applicable to brittle materials. In SD, laser beam of specific wave length is focused and scanned inside of the material to produce a SD-process zone which includes an array of microvoids. Each microvoid is thought to be received an excessive internal pressure due to thermal expansion and then material is split along a plane which contains an array of microvoids. After the mechanical splitting process, there expected to present a considerable residual stresses in the vicinity of an array of microvoids exposed at the splitting surface. In the present study, by analyzing the elastic-plastic stress fields near the array of surface microvoids, the mechanical characteristics of the SD induces surface is discussed.

Stresses in Thick-Walled Cylinders: A Simple and Insightful Treatment

1995 ◽  
Vol 23 (3) ◽  
pp. 237-244
Author(s):  
M. J. French ◽  
M. B. Widden
Keyword(s):  
Residual Stresses ◽  
Internal Pressure ◽  
Pressure Calculation ◽  
Walled Cylinder

The paper introduces a method for finding stresses in thick-walled cylinders which is more direct than the usual technique. By reducing markedly the amount of algebra needed, the method helps students to see clearly how a thick-walled cylinder withstands internal pressure. Calculation of the interference needed in shrink-fitted cylinders, and of the residual stresses following autofrettage, are greatly simplified using the method.

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