Paris Fatigue Life Modeling of Pressure Vessel Service Simulation Tests

2012 ◽  
Vol 134 (5) ◽  
Author(s):  
John H. Underwood ◽  
John J. Keating ◽  
Edward Troiano ◽  
Gregory N. Vigilante
Keyword(s):  
Fatigue Life ◽  
Residual Stresses ◽  
Pressure Vessel ◽  
Base Alloy ◽  
Pressure Vessels ◽  
Full Scale ◽  
Test Results ◽  
X Ray Diffraction ◽  
Life Model ◽  
Nickel Base

Results from four groups of full-scale pressure vessel service simulation tests are described and analyzed using Paris fatigue life modeling. The objective is to determine how the vessel and initial crack configurations and applied and residual stresses control the as-tested fatigue life of the vessel. The tube inner radii are in the 40–80 mm range; wall thickness varies from 6 to 80 mm; materials are ASTM A723 pressure vessel steel and IN718 nickel-base alloy; applied internal pressure varies from 90 to 700 MPa. The Paris constant, C, and exponent, m, that describe the fatigue crack propagation rate versus stress intensity factor range for the various vessel materials, were measured as part of the investigation. Extensive, previously published fatigue life results from baseline A723 pressure vessels with well characterized autofrettage residual stresses and C and m values are used to demonstrate that a Paris fatigue life model gives a good description of the measured life. The same model is then used to determine the variables with predominant control over life in three types of pressure vessel for which less information and tests results are available. A design life for pressure vessels is calculated for a specified very low probability of fatigue failure using the log(N)-normal distribution statistics often used for fatigue of structures. The results of the work showed: (i) X-ray diffraction measurements of through-wall autofrettage residual stresses are in excellent agreement with prior neutron diffraction measurements from a baseline autofrettaged A723 pressure vessel; these verified autofrettage residual stresses then provide critical input to the baseline Paris life modeling; (ii) comparison of the various full-scale fatigue test results with results from the Paris fatigue life model shows close agreement when autofrettage residual stresses are incorporated into models; (iii) model results for A723 steel vessels with yield strength reduced from the initial 1400 MPa value and degree of autofrettage increased from the initial 40% value indicates a significantly improved resistance to brittle failure with no loss of fatigue life; (iv] comparison of model fatigue life results for IN718 nickel-base alloy vessels with their full-scale test results is improved when near-bore residual stresses measured by X-ray diffraction are included in the model calculations.

Kendall Analysis of Cannon Pressure Vessels

2012 ◽  
Author(s):  
John H. Underwood
Keyword(s):  
Fatigue Life ◽  
Yield Strength ◽  
Pressure Vessel ◽  
Structural Integrity ◽  
Pressure Vessels ◽  
Full Scale ◽  
Compressive Yield Strength ◽  
Us Army ◽  
Post Test ◽  
Engineering Mechanics

Engineering mechanics analysis of cannon pressure vessels is described with special emphasis on the work of the late US Army Benet Laboratories engineer David P. Kendall. His work encompassed a broad range of design and analysis of high pressure vessels for use as cannons, including analysis of the limiting yield pressure for vessels, the autofrettage process applied to thick vessels, and the fatigue life of autofrettaged cannon vessels. Mr. Kendall’s work has become the standard approach used to analyze the structural integrity of cannon pressure vessels at the US Army Benet Laboratories. The methods used by Kendall in analysis of pressure vessels were simple and direct. He used classic results from research in engineering mechanics to develop descriptive expressions for limiting pressure, autofrettage residual stresses and fatigue life of cannon pressure vessels. Then he checked the expressions against the results of full-scale cannon pressure vessel tests in the proving grounds and the laboratory. Three types of analysis are described: [i] Yield pressure tests of cannon sections compared with a yield pressure expression, including in the comparison post-test yield strength measurements from appropriate locations of the cannon sections; [ii] Autofrettage hoop residual stress measurements by neutron diffraction in cannon sections compared with expressions, including Bauschinger corrections in the expressions to account for the reduction in compressive yield strength near the bore of an autofrettaged vessel; [iii] Fatigue life tests of cannons following proving ground firing and subsequent laboratory simulated firing compared with Paris-based fatigue life expressions that include post-test metallographic determination of the initial crack size due to firing. Procedures are proposed for Paris life calculations for bore-initiated fatigue affected by crack-face pressure and notch-initiated cracking in which notch tip stresses are significantly above the material yield strength. The expressions developed by Kendall and compared with full-scale cannon pressure vessel tests provide useful first-order design and safety checks for pressure vessels, to be followed by further engineering analysis and service simulation testing as appropriate for the application. Expressions are summarized that are intended for initial design calculations of yield pressure, autofrettage stresses and fatigue life for pressure vessels. Example calculations with these expressions are described for a hypothetical pressure vessel.

The Measurement and Modelling of Residual Stresses in a Full-Scale BWR Shroud-Support Mock-Up

2008 ◽  
Author(s):  
K. Ogawa ◽  
E. J. Kingston ◽  
D. J. Smith ◽  
T. Saito ◽  
R. Sumiya ◽  
...  
Keyword(s):  
Residual Stresses ◽  
Pressure Vessel ◽  
Base Alloy ◽  
Kinematic Hardening ◽  
Full Scale ◽  
Hole Drilling ◽  
Outer Diameter ◽  
Butt Weld ◽  
Support Leg ◽  
Hoop Direction

This paper presents results from a programme of residual stress measurements and modelling carried out in Japan on a full-scale mock-up of the hemi-spherical base of a Boiling Water Reactor (BWR) pressure vessel. The shroud support mock-up consisted of four main parts: pressure vessel, support plate, support cylinder and support legs. The mock-up was manufactured using a combination of ferritic steel and nickel base alloy (i.e. alloys: 82, 182 and 600) in a similar manner to that of the actual component. Overall the mock-up had an outer diameter of 6.6m and a height of 3.4m. The residual stresses generated by the nickel alloy welds during manufacture were measured using the Deep-Hole Drilling (DHD) [1–3] and Sectioning [4, 5] techniques, and modelled using ABAQUS. Presented here are measurement and modelling results from three weld locations within the mock-up: at one location through the “double-bevel” butt-weld joining the top of the support leg to the support cylinder (named H10) and at two locations through the “asymmetric double-V” weld joining the bottom of the support leg to the cladded pressure vessel (named H11a and H11b). The semi-destructive DHD technique was carried out first at all three locations on-site in Japan before the fully destructive Sectioning technique was used. Both techniques measured the biaxial (i.e. mock-up-hoop and -axial) residual stresses. The DHD and Sectioning techniques were not carried out at the exact same locations, rather similar locations due to the axisymmetry of the mock-up. Modelling of the residual stresses generated was undertaken for each weld location using a 2D axisymmetric finite element analysis containing between 40–50 discrete weld beads. The modelled residual stresses were generated using thermal load modelling followed by elastic-plastic mechanical analysis under kinematic hardening rules. Overall there is excellent agreement between the measured and modelled residual stresses at all locations. At all locations the measured peak tensile residual stresses (i.e. H10 = 410MPa, H11a = 260MPa and H11b = 230MPa) were found to be in the hoop direction just below the inner weld cap surface. The modelled peak tensile residual stresses were again found in the hoop direction near the inner weld capped surface, however, they were found to be approximately 155MPa greater than the measured residual stresses, and for locations H10 and H11a similar peaks were found near the outer weld cap surface as well.

A Study on Fatigue Life Evaluation of Pressure Vessel Made of ASME SA240-316L Material Using Numerical Analysis

2019 ◽  
Vol 893 ◽  
pp. 1-5 ◽  
Author(s):  
Eui Soo Kim
Keyword(s):  
Finite Element ◽  
Fatigue Life ◽  
Pressure Vessel ◽  
Life Prediction ◽  
Pressure Vessels ◽  
Physical Damage ◽  
Element Analysis ◽  
Internal Damage ◽  
Life Evaluation ◽  
Fatigue Life Evaluation

Pressure vessels are subjected to repeated loads during use and charging, which can causefine physical damage even in the elastic region. If the load is repeated under stress conditions belowthe yield strength, internal damage accumulates. Fatigue life evaluation of the structure of thepressure vessel using finite element analysis (FEA) is used to evaluate the life cycle of the structuraldesign based on finite element method (FEM) technology. This technique is more advanced thanfatigue life prediction that uses relational equations. This study describes fatigue analysis to predictthe fatigue life of a pressure vessel using stress data obtained from FEA. The life prediction results areuseful for improving the component design at a very early development stage. The fatigue life of thepressure vessel is calculated for each node on the model, and cumulative damage theory is used tocalculate the fatigue life. Then, the fatigue life is calculated from this information using the FEanalysis software ADINA and the fatigue life calculation program WINLIFE.

A Study of Nozzles in Pressure Vessels under Pressure Fatigue Loading

1967 ◽  
Vol 182 (1) ◽  
pp. 657-684 ◽  
Author(s):  
J. Spence ◽  
W. B. Carlson
Keyword(s):  
Fatigue Life ◽  
Mild Steel ◽  
Pressure Vessel ◽  
Special Interest ◽  
Maximum Stress ◽  
Fatigue Loading ◽  
Fatigue Tests ◽  
Pressure Vessels ◽  
Full Size

Nozzles in cylindrical vessels have been of special interest to designers for some time and have offered a field of activity for many research workers. This paper presents some static and fatigue tests on five designs of full size pressure vessel nozzles manufactured in two materials. Supporting and other published work is reviewed showing that on the basis of the same maximum stress mild steel vessels give the same fatigue life as low alloy vessels. When compared on the basis of current codes it is shown that mild steel vessels may have five to ten times the fatigue life of low alloy vessels unless special precautions are taken.

Stress and Fatigue Life Modeling of Cannon Breech Closures Including Effects of Material Strength and Residual Stress

2000 ◽  
Vol 123 (1) ◽  
pp. 150-154
Author(s):  
John H. Underwood ◽  
Michael J. Glennon
Keyword(s):  
Residual Stress ◽  
Finite Element ◽  
Fatigue Life ◽  
Yield Strength ◽  
Residual Stresses ◽  
Solid Mechanics ◽  
Element Model ◽  
Pressure Vessels ◽  
Material Strength ◽  
Element Analysis

Laboratory fatigue life results are summarized from several test series of high-strength steel cannon breech closure assemblies pressurized by rapid application of hydraulic oil. The tests were performed to determine safe fatigue lives of high-pressure components at the breech end of the cannon and breech assembly. Careful reanalysis of the fatigue life tests provides data for stress and fatigue life models for breech components, over the following ranges of key parameters: 380–745 MPa cyclic internal pressure; 100–160 mm bore diameter cannon pressure vessels; 1040–1170 MPa yield strength A723 steel; no residual stress, shot peen residual stress, overload residual stress. Modeling of applied and residual stresses at the location of the fatigue failure site is performed by elastic-plastic finite element analysis using ABAQUS and by solid mechanics analysis. Shot peen and overload residual stresses are modeled by superposing typical or calculated residual stress distributions on the applied stresses. Overload residual stresses are obtained directly from the finite element model of the breech, with the breech overload applied to the model in the same way as with actual components. Modeling of the fatigue life of the components is based on the fatigue intensity factor concept of Underwood and Parker, a fracture mechanics description of life that accounts for residual stresses, material yield strength and initial defect size. The fatigue life model describes six test conditions in a stress versus life plot with an R2 correlation of 0.94, and shows significantly lower correlation when known variations in yield strength, stress concentration factor, or residual stress are not included in the model input, thus demonstrating the model sensitivity to these variables.

Measurements of Stress During Thermal Shock in Clad Reactor Pressure Vessel Material Using Time-Resolved In-Situ Synchrotron X-Ray Diffraction

2018 ◽  
Author(s):  
Sam Oliver ◽  
Chris Simpson ◽  
Andrew James ◽  
Christina Reinhard ◽  
David Collins ◽  
...  
Keyword(s):  
Thermal Shock ◽  
Pressure Vessel ◽  
Pressure Vessels ◽  
Reactor Pressure Vessel ◽  
Pressure Vessel Steel ◽  
X Ray Diffraction ◽  
Time Resolved ◽  
Vessel Steel ◽  
X Ray ◽  
Reactor Pressure

Nuclear reactor pressure vessels must be able to withstand thermal shock due to emergency cooling during a loss of coolant accident. Demonstrating structural integrity during thermal shock is difficult due to the complex interaction between thermal stress, residual stress, and stress caused by internal pressure. Finite element and analytic approaches exist to calculate the combined stress, but validation is limited. This study describes an experiment which aims to measure stress in a slice of clad reactor pressure vessel during thermal shock using time-resolved synchrotron X-ray diffraction. A test rig was designed to subject specimens to thermal shock, whilst simultaneously enabling synchrotron X-ray diffraction measurements of strain. The specimens were extracted from a block of SA508 Grade 4N reactor pressure vessel steel clad with Alloy 82 nickel-base alloy. Surface cracks were machined in the cladding. Electric heaters heat the specimens to 350°C and then the surface of the cladding is quenched in a bath of cold water, representing thermal shock. Six specimens were subjected to thermal shock on beamline I12 at Diamond Light Source, the UK’s national synchrotron X-ray facility. Time-resolved strain was measured during thermal shock at a single point close to the crack tip at a sample rate of 30 Hz. Hence, stress intensity factor vs time was calculated assuming K-controlled near-tip stress fields. This work describes the experimental method and presents some key results from a preliminary analysis of the data.

A Study of Phase Reactions in a Complex 4.5 Al–3.5 Ti–Ni Base Alloy

1960 ◽  
Vol 4 ◽  
pp. 233-243
Author(s):  
John F. Radavich ◽  
W. J. Boesch
Keyword(s):  
Electron Microscopy ◽  
High Temperature ◽  
Structural Changes ◽  
Base Alloy ◽  
Phase Changes ◽  
X Ray Diffraction ◽  
High Temperature Alloy ◽  
X Ray ◽  
Nickel Base ◽  
Precipitated Phases

AbstractAn investigation of the phase changes in a complex aluminum-titanium-hardened nickel-base high-temperature alloy was carried out after solutioning at high temperatures and aging at lower temperatures. The physical distribution and size of the precipitated phases were studied by electron microscopy. X-ray diffraction and fluorescence analyses were carried out on chemically extracted residues. The results of the xtructure changes as well as correlation of some physical properties with the structural changes are presented.

Investigation of Residual Stresses in a Sleeve Coldworked Lug Specimen by Neutron and X-ray Diffraction

1994 ◽  
Vol 38 ◽  
pp. 455-461
Author(s):  
R. Lin ◽  
B. Jaensson ◽  
T. M. Holden ◽  
R. B. Rogge ◽  
J. H. Root
Keyword(s):  
Fatigue Life ◽  
Residual Stresses ◽  
Fatigue Cracks ◽  
Fatigue Properties ◽  
Aircraft Industry ◽  
X Ray Diffraction ◽  
X Ray ◽  
Initiation And Propagation ◽  
Structural Parts ◽  
Compressive Residual Stresses

Sleeve coldworking (SCW) is a mechanical process used in the aircraft industry to strengthen fastener holes of structural parts. By cold-expanding the holes, compressive residual stresses and a high dislocation density are introduced around the holes, the effect of which is to counteract the initiation and propagation of fatigue cracks and thus increase the fatigue life of the parts. The knowledge of residual stress due to SCW is therefore crucial for assessing the fatigue properties of a treated part. In this study, residual stresses were investigated, by employing neutron and X-ray diffraction methods, in a lug specimen that was sleeve coldworked and fatigued. The specimen had been used for testing the influence of the SCW process on fatigue life and crack propagation behaviour under constant amplitude or variable amplitude cyclic loading.

Discussion

1965 ◽  
Vol 285 (1400) ◽  
pp. 141-174 ◽  
Keyword(s):  
Pressure Vessel ◽  
Crack Extension ◽  
Initial Crack ◽  
Pressure Vessels ◽  
Full Scale ◽  
Small Specimen ◽  
Starting Point ◽  
Specimen Test ◽  
Valid Test ◽  
The One

It is our purpose to review fracture characteristics of heavy-walled pressure vessels in relation to the plane-strain crack toughness known under the term, K Ic . As a starting point, suppose that direct measurement of the strength of a full-scale pressure vessel containing a specific crack is contemplated. An initial crack of approximately the desired size can be introduced in several ways, for example, by inserting a sharp groove and then vibrating that region until a fatigue crack develops. However, full-scale testing is often impractical either for reasons of expense or because the introduction of in-service damage, say by nuclear irradiation, is not feasible at the full-scale size. Furthermore, valid test results can usually be obtained at much smaller scale. Small specimen fracture tests Crack extension behaviour observed in a small specimen test can be regarded as representative of full-scale fracture behaviour so long as the stresses carried by the surrounding material into the region containing the crack receive adequate representation. Since the specimen size desired for irradiation purposes is quite limited, we consider next whether crack extension of a large part-through crack in a thick-walled pressure vessel can be modelled by testing just the slice of material indicated in figures 108 ( a ) and ( b ). The calibration and use of test specimens similar to the one shown in figure 108( b ) are described by Sullivan (1964).

Revised and New Proposal of Environmental Fatigue Life Correction Factor (Fen) for Carbon and Low-Alloy Steels and Nickel Base Alloys in LWR Water Environments

2006 ◽  
Author(s):  
Makoto Higuchi ◽  
Katsumi Sakaguchi ◽  
Akihiko Hirano ◽  
Yuichiro Nomura
Keyword(s):  
Fatigue Life ◽  
Dissolved Oxygen ◽  
Strain Rate ◽  
Test Data ◽  
Base Alloy ◽  
Low Cycle Fatigue ◽  
Low Alloy Steels ◽  
Alloy Steels ◽  
Nickel Base ◽  
Fatigue Life Reduction

Low cycle fatigue life of carbon and low alloy steels reduces remarkably as functions of strain rate, temperature, dissolved oxygen and sulfur in steel in high temperature water simulating LWR coolant. A model for predicting such fatigue life reduction was first proposed in the early 1980s and since then has been revised several times. The existing model established in 2000 is used for the MITI Guideline [6] and the TENPES Guideline [7] which stipulate procedures for evaluating environmental fatigue damage at LWR plants in Japan. This paper presents the most recent environmental fatigue evaluation model derived based on additional fatigue data provided by the EFT Project over the past five years. This model differs not significantly with previous version but does provide more accurate equations for the susceptibility of fatigue life to sulfur in steel, strain rate, temperature and dissolved oxygen. Test data on environmental fatigue of nickel base alloys are available only to a limited extent and there is yet no model for predicting fatigue life reduction in such an environment. The EFT Project has made available considerable environmental fatigue test data and developed a new model for calculating Fen of nickel base alloys. The contribution of environment to fatigue of nickel base alloy is much less compared to that in austenitic stainless steel.

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