Displacement Based Failure Criterion Applicable to Finite Element Analysis Results for Wall-Thinned Pipes Under Pressure Load

2013 ◽  
Author(s):  
Toshiyuki Meshii ◽  
Kan Yoshii
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Failure Criterion ◽  
Large Strain ◽  
True Strain ◽  
Burst Pressure ◽  
Pipe Material ◽  
Element Analysis ◽  
Hardening Material ◽  
Displacement Based

In this work, a failure criterion applicable to large strain elastic-plastic Finite Element Analysis (EP FEA) results was proposed in order to predict the burst pressure of wall-thinned straight pipes. The key finding was that, though the pipe material was strain-hardening material, and though the pipe was locally wall-thinned, the outer surface radial displacement at the flaw center obtained from the EP FEA tended to diverge with the increase in pressure, even though the strain was very low compared to the true strain of fracture. This tendency was validated by the image processing displacement measurement results from the systematic burst tests of wall-thinned pipes. By comparing the EP-FEA results with the test results, the proposed criterion predicted the burst pressure within a maximum 10% difference. Advantage of the criterion is that it uses the true stress and strain relationship below the true tensile strength, and the ambiguous near fracture relationship is not necessary.

Cross-Weld Tensile Properties of Girth Welds for Strain-Based Designed Pipelines

2006 ◽  
Author(s):  
J. T. Bowker ◽  
J. A. Gianetto ◽  
G. Shen ◽  
W. Tyson ◽  
D. Horsley
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Stress Concentration ◽  
Weld Metal ◽  
Tensile Properties ◽  
True Strain ◽  
Standard Test ◽  
Pipe Material ◽  
Lower Stress ◽  
Element Analysis

For strain-based designed pipelines it is important to understand the relative tensile properties of both weld metal and pipe material in the pipe axial direction. The evaluation of weld metal tensile properties has typically involved extracting all-weld-metal tensile samples in the direction of the weld. In this study an evaluation of the application of “waisted” tensile samples to generate data has been conducted. Initial studies focused on finite element analysis to generate geometry factors for a range of specimen configurations to correct for the level of stress triaxiality. These factors were then applied to samples extracted from X70 and X100 pipe material to establish the validity of this approach. It was shown that, regardless of the radius of waisted specimens, very good agreement was obtained between the geometry-factor-corrected stress-strain curves and those generated from standard test specimens at true strains above 0.02. To achieve a better agreement between the corrected and standard tensile curves in and around yield it was necessary to use samples with a large radius (9 mm) where the stress concentration was low. Finite element analysis provided supporting evidence with respect to the effect of stress concentration associated with different specimen radii on the yielding pattern. These waisted samples were used to measure the tensile properties in all-weld-metal and cross-weld-metal directions for an X70 double joint (DJ) weld and an X100 mechanized pulsed gas metal arc (P-GMA) weld. Waisted samples taken from the double joint weld on X70 with radii of 3 mm and 9 mm showed no difference with respect to their orientation. Once stress-strain behaviour was corrected for geometry, the curves were in excellent agreement with the standard test specimens above 0.01 true strain in the case of the sample of radius 3 mm and for the whole curve for the sample with radius 9 mm. An assessment of the X100 weld identified a small difference between all-weld-metal and cross-weld-metal directions, with the latter displaying a lower stress between yielding and 0.03 true strain. The use of waisted samples of larger radius generated much better agreement with the standard specimens associated with their lower stress concentration. Because of the finite weld width, consideration needs to be given to the extent to which the reduced section may extend beyond the weld and the potential effect of mismatch in strength.

Finite Element Analysis of Burst Pressure for Pipelines With Long Corrosion Defects

2012 ◽  
Author(s):  
Xian-Kui Zhu ◽  
Brian N. Leis
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Failure Criterion ◽  
Equivalent Stress ◽  
Theoretical Solution ◽  
Burst Pressure ◽  
Element Analysis ◽  
Integrity Assessment ◽  
Corrosion Defects ◽  
Von Mises

Plastic collapse analysis and remaining burst strength determination are critical to a corroded pipeline in its fitness-for-service analysis and integrity assessment. For very long corrosion defects, the present authors proposed a theoretical solution for predicting the burst pressure of corroded pipe in terms of a newly developed average shear stress yield theory, and validated it using full-scale burst data for long real corrosion defects. This paper then presents a finite element analysis (FEA) procedure to determine the remaining burst pressure for a very long blunt defect. A burst failure criterion that is referred to as von Mises equivalent stress criterion is proposed first in reference to the von Mises theory. Detailed elastic-plastic FEA calculations are performed using ABAQUS for a series of corroded pipes with infinitely long defects in different widths. From the FEA results and using the proposed failure criterion, the numerical results of burst pressure are determined for the long defects. The results show that using the proposed failure criterion, the FEA simulation can accurately determine the burst pressure for corroded pipes with long defects that is consistent with the theoretical solution. The conventional assessment methods including ASME B31G, RSTRENG, PCORRC and LPC are also evaluated and discussed in comparison with the proposed theoretical solution of burst pressure for long corrosion defects.

scholarly journals Elastic-Plastic Failure Analysis of Pressure Burst Tests of Thin Toroidal Shells

1999 ◽  
Vol 121 (2) ◽  
pp. 149-153 ◽  
Author(s):  
D. P. Jones ◽  
J. E. Holliday ◽  
L. D. Larson
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Large Strain ◽  
Structural Instability ◽  
Burst Pressure ◽  
Bursting Pressure ◽  
Element Analysis ◽  
Elastic Plastic ◽  
Toroidal Shells ◽  
Good Agreement

This paper provides a comparison between test and analysis results for bursting of thin toroidal shells. Testing was done by pressurizing two toroidal shells until failure by bursting. An analytical criterion for bursting is developed based on good agreement between structural instability predicted by large strain-large displacement elastic-plastic finite element analysis and observed burst pressure obtained from test. The failures were characterized by loss of local stability of the membrane section of the shells consistent with the predictions from the finite element analysis. Good agreement between measured and predicted burst pressure suggests that incipient structural instability as calculated by an elastic-plastic finite element analysis is a reasonable way to calculate the bursting pressure of thin membrane structures.

Burst Pressure of Pressurized Cylinders With Hillside Nozzle

2009 ◽  
Vol 131 (4) ◽  
Author(s):  
H. F. Wang ◽  
Z. F. Sang ◽  
L. P. Xue ◽  
G. E. O. Widera
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Experimental Models ◽  
Burst Pressure ◽  
Element Analysis ◽  
Test Models ◽  
Scale Test ◽  
Failure Location ◽  
Dimensional Instability ◽  
Good Agreement

The burst pressure of cylinders with hillside nozzle is determined using both experimental and finite element analysis (FEA) approaches. Three full-scale test models with different angles of the hillside nozzle were designed and fabricated specifically for a hydrostatic test in which the cylinders were pressurized with water. 3D static nonlinear finite element simulations of the experimental models were performed to obtain the burst pressures. The burst pressure is defined as the internal pressure for which the structure approaches dimensional instability, i.e., unbounded strain for a small increment in pressure. Good agreement between the predicted and measured burst pressures shows that elastic-plastic finite element analysis is a viable option to estimate the burst pressure of the cylinders with hillside nozzles. The preliminary results also suggest that the failure location is near the longitudinal plane of the cylinder-nozzle intersection and that the burst pressure increases slightly with an increment in the angle of the hillside nozzle.

Development of Material Constants for Nonlinear Finite-Element Analysis

1988 ◽  
Vol 61 (5) ◽  
pp. 879-891 ◽  
Author(s):  
Robert H. Finney ◽  
Alok Kumar
Keyword(s):  
Experimental Data ◽  
Finite Element Analysis ◽  
Finite Element ◽  
Large Strain ◽  
Strain Range ◽  
Nonlinear Finite Element ◽  
Element Analysis ◽  
Material Models ◽  
Tensile Data

Abstract The determination of the material coefficients for Ogden, Mooney-Rivlin, Peng, and Peng-Landel material models using simple ASTM D 412 tensile data is shown to be a manageable task. The application of the various material models are shown to be subject to the type and level of deformation expected, with Ogden showing the best correlation with experimental data over a large strain range for the three types of strain investigated. At low strains, all of the models showed reasonable correlation.

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