Modification and Extension of Screening Criteria for Fatigue Analysis

2019 ◽  
Vol 142 (1) ◽  
Author(s):  
Jun Shen ◽  
Mingwan Lu ◽  
Zhenyu Wang ◽  
Heng Peng ◽  
Yinghua Liu
Keyword(s):  
Fatigue Curve ◽  
Fatigue Analysis ◽  
Allowable Stress ◽  
Design Factor ◽  
Screening Criteria ◽  
Asme Code ◽  
Applicable Range ◽  
Number Of Cycles ◽  
Design Pressure

Abstract ASME Code VIII-2-2019 and previous versions provided three screening criteria for fatigue analysis. From edition 2004 to 2019, the design factor for material allowable stress decreased and the considered range of permissible cyclic number for design fatigue curve extended. However, screening criteria are almost unchanged except one restriction: If the specified number of cycles is greater than 106, then the screening criteria are not applicable and a fatigue analysis is required. In this paper, percentage limit of the design pressure in method A is modified and the specified number of cycles is extended. Some revision suggestions are also proposed to broaden the applicable range of the screening criterion.

Modification and Extension of Screening Criteria for Fatigue Analysis

2019 ◽  
Author(s):  
Jun Shen ◽  
Mingwan Lu ◽  
Zhenyu Wang ◽  
Heng Peng ◽  
Yinghua Liu
Keyword(s):  
Fatigue Curve ◽  
Fatigue Analysis ◽  
Allowable Stress ◽  
Design Factor ◽  
Screening Criteria ◽  
Asme Code ◽  
Applicable Range ◽  
Number Of Cycles ◽  
Design Pressure

Abstract ASME Code VIII-2-2017 and previous versions provided three screening criteria for fatigue analysis. From Edition 2004 to 2017, the design factor for material allowable stress decreased and the considered range of permissible cyclic number for design fatigue curve extended. However, screening criterion are almost unchanged except one restriction: If the specified number of cycles is greater than 106, then the screening criteria are not applicable and a fatigue analysis is required. In this paper, percentage limit of the design pressure in Method A is modified and the specified number of cycles is extended. Some revision suggestions are also proposed to broaden the applicable range of the screening criterion.

Applications of Code Case 2605 for Fatigue Evaluation of Vessels Made in 2.25Cr-1Mo-0.25V Steels Slightly Into Creep Range

2010 ◽  
Author(s):  
Susumu Terada
Keyword(s):  
Fatigue Curve ◽  
Time Dependent ◽  
Inelastic Analysis ◽  
Asme Code ◽  
Section Viii ◽  
Preliminary Study ◽  
Number Of Cycles ◽  
Fatigue Evaluation ◽  
Division 2 ◽  
Made In

The current Section VIII Division 2 of ASME code does not permit method A of paragraph 5.5.2.3 to be used for the exemption from fatigue analysis when the design allowable stress is taken in the time dependent temperature range. Method B of paragraph 5.5.2.4 also cannot be used because it requires the use of the fatigue curve which is limited to 371 ° C and below the needed temperature. Code Case 2605 is a rule for fatigue evaluation of 2.25Cr-1Mo-0.25V steels at temperatures greater than 371 ° C and less than 454 ° C. An inelastic analysis including the effect of creep shall be performed for all pressure parts according to Code Case 2605. Especially, a full inelastic analysis shall be performed using the actual time-dependent thermal and mechanical loading histograms for the lateral nozzle based on preliminary study. It takes much time to perform this inelastic analysis for all full histograms and obtain the fatigue evaluation results when large number of cycles of full pressure is specified in user’s design specification. This paper provides sample analysis results for nozzles and clarifies issue of implementation of Code Case 2605. Then, the proposal of simplification and modification of Code Case 2605 from these results are proposed.

Application of Code Case 2605 for Fatigue Evaluation of Vessels Made in 2.25Cr-1Mo-0.25V Steels Slightly Into Creep Range

2013 ◽  
Vol 135 (4) ◽  
Author(s):  
Susumu Tereda
Keyword(s):  
Screening Method ◽  
Fatigue Analysis ◽  
Allowable Stress ◽  
Sample Analysis ◽  
Inelastic Analysis ◽  
Asme Code ◽  
Section Viii ◽  
Fatigue Evaluation ◽  
Division 2 ◽  
Made In

The current Section VIII Division 2 of ASME code permits only the method based on experience with comparable equipment of paragraph 5.5.2.2 to be used for the exemption from fatigue analysis when the design allowable stress is taken in the time dependent temperature range and the specified minimum tensile strength is greater than 552 MPa. In the case of 2.25Cr-1Mo-0.25V steels, the allowable stress of new Div.2 is higher than that of the old Div.2. Therefore, there are no experiences with comparable equipment. Code Case 2605-1 provides rules for fatigue evaluation of 2.25Cr-1Mo-0.25V steels at temperatures greater than 371 °C and equal to or less than 454 °C. An inelastic analysis including the effect of creep is required to be performed for all pressure parts according to Code Case 2605-1. There are six and more types of nozzles in each hydro-processing reactor. The inelastic analyses shall be performed for all types of nozzles. The simplified screening method for fatigue analyses and the simplified fatigue analysis procedure need to be developed because it takes much time to perform inelastic analyses. This paper provides sample analysis results for various types of nozzles and clarifies issue with respect to implementation of Code Case 2605-1. Then, a proposal for simplification and modification of Option 1 and Option 2 fatigue evaluation methods for nozzles of Code Case 2605-1 are proposed from these investigations.

Strain Measures for Fatigue Assessment Using Elastic-Plastic FEA

2005 ◽  
Author(s):  
W. Reinhardt
Keyword(s):  
Strain Range ◽  
Fatigue Curve ◽  
Fatigue Analysis ◽  
Plastic Strain Range ◽  
Elastic Plastic ◽  
Asme Code ◽  
The Mean ◽  
Mean Cycle ◽  
Strain Measures ◽  
Cycle Temperature

In the ASME Code, Section III NB-3228.4(c) requires that if an elastic-plastic fatigue analysis is performed, the fatigue curve shall be entered with the numerically maximum principal total (elastic plus plastic) strain range multiplied by one-half the modulus of elasticity of the material at the mean cycle temperature. This paper discusses the choice of the principal strain range as well as other possible strain range measures for elastic-plastic fatigue analysis. Several generic observations that form the basis for the discussion are outlined.

Statistical Analyses of High Cycle Fatigue French Data for Austenitic SS

2014 ◽  
Author(s):  
Géraud Blatman ◽  
Thomas Métais ◽  
Jean-Christophe Le Roux ◽  
Simon Cambier
Keyword(s):  
Strain Amplitude ◽  
High Cycle Fatigue ◽  
Experimental Testing ◽  
Austenitic Stainless Steels ◽  
Fatigue Curve ◽  
Statistical Analyses ◽  
Starting Point ◽  
The Mean ◽  
Number Of Cycles ◽  
Selection Of

In the 2009 version of the ASME BPV Code, a set of new design fatigue curves were proposed to cover the various steels of the code. These changes occurred in the wake of publications [1] showing that the mean air curve used to build the former ASME fatigue curve did not always represent accurately laboratory results. The starting point for the methodology to build the design curve is the mean air curve obtained through laboratory testing: coefficients are then applied to the mean air curve in order to bridge the gap between experimental testing and reactor conditions. These coefficients on the number of cycles and on the strain amplitude are equal to 12 and 2 respectively in the 2009 ASME BPV code, using the mean air curve proposal from NUREG/CR-6909 [1]. Internationally, with the same mean air curve, other proposals have emerged and especially in France [2]-[3] where a consensus seems to be reached on the reduction of the coefficient on strain amplitude. This paper provides statistical analyses of the experimental data obtained in France at high-cycle for austenitic stainless steels. It enables to bring arguments for the selection of a coefficient on strain amplitude in the French RCC-M code, where less scatter on the data is witnessed due to fewer material grades.

Strength Evaluation for Pressure-Containing Parts of Ultra-High-Pressure Compressor by Using Standards of Ultra-High-Pressure Gas Equipment

2011 ◽  
Author(s):  
Yohei Tanno ◽  
Tomohiro Naruse ◽  
Shigeru Arai ◽  
Shinichiro Kurita
Keyword(s):  
High Pressure ◽  
Fatigue Strength ◽  
Absorbed Energy ◽  
Ultra High Pressure ◽  
High Pressure Compressor ◽  
Asme Code ◽  
American Standard ◽  
Leak Before Break ◽  
Design Pressure ◽  
Pressure Compressor

The Japanese standard “KHK-S-0220” (KHK-code) and the American standard “Boiler and Pressure Vessel Code Sec.8 Div.3” (ASME-code) concerning ultra-high-pressure gas equipment were applied to Hitachi’s ultra-high-pressure compressor, and a series of strength evaluations were carried out. Hitachi produces and maintains ultra-high-pressure reciprocating compressors with a design pressure over 200 MPa. In Japan, ultra-high pressure gas equipment over 100 MPa must be designed according to KHK-code established by the High Pressure Gas Safety Institute of Japan. This Japanese standard was applied to an ultra-high-pressure compressor, and design pressure limits, shakedown limits, required absorbed energy of materials, leak-before-break (LBB), and fatigue strength were evaluated. ASME-code was also applied to the compressor, and strength evaluations like the above were carried out. As a result, it was found that KHK-code and ASME-code gave conservative evaluation of fatigue strength for an ultra-high-pressure compressor.

Alternative RTNDT for Linde 80 Weld Materials

2002 ◽  
Author(s):  
K. K. Yoon ◽  
J. B. Hall
Keyword(s):  
Fracture Toughness ◽  
Transition Temperature ◽  
Pressure Vessel ◽  
Nuclear Power ◽  
Power Plants ◽  
Pressure Vessels ◽  
Screening Criteria ◽  
Master Curve Method ◽  
Asme Code ◽  
Curve Method

The ASME Boiler and Pressure Vessel Code provides fracture toughness curves of ferritic pressure vessel steels that are indexed by a reference temperature for nil ductility transition (RTNDT). The ASME Code also prescribes how to determine RTNDT. The B&W Owners Group has reactor pressure vessels that were fabricated by Babcock & Wilcox using Linde 80 flux. These vessels have welds called Linde 80 welds. The RTNDT values of the Linde 80 welds are of great interest to the B&W Owners Group. These RTNDT values are used in compliance of the NRC regulations regarding the PTS screening criteria and plant pressure-temperature limits for operation of nuclear power plants. A generic RTNDT value for the Linde 80 welds as a group was established by the NRC, using an average of more than 70 RTNDT values. Emergence of the Master Curve method enabled the industry to revisit the validity issue surrounding RTNDT determination methods. T0 indicates that the dropweight test based TNDT is a better index than Charpy transition temperature based index, at least for the RTNDT of unirradiated Linde 80 welds. An alternative generic RTNDT is presented in this paper using the T0 data obtained by fracture toughness tests in the brittle-to-ductile transition temperature range, in accordance with the ASTM E1921 standard.

JSME Construction Standard for Superconducting Magnet of Fusion Facility “Procedure for Structural Design”

2009 ◽  
Author(s):  
Yukio Takahashi ◽  
Shigeru Tado ◽  
Kazunori Kitamura ◽  
Masataka Nakahira ◽  
Junji Ohmori ◽  
...  
Keyword(s):  
Stainless Steels ◽  
Structural Design ◽  
Structural Integrity ◽  
Superconducting Magnets ◽  
Austenitic Stainless Steels ◽  
Superconducting Magnet ◽  
Fatigue Curve ◽  
Stress System ◽  
Allowable Stress ◽  
Fatigue Assessment

Superconducting magnets are structures which have an important role in Tokamak-type fusion reactor plants. They are huge and complicated structures exposed to very low temperature, 4K and the methods for keeping their integrity need to be newly developed. To maintain their structural integrity during the plant operation, a procedure for structural design was developed as a part of JSME Construction Standard for Superconducting Magnet. General structures and requirements of this procedure basically follow those of class 1 and class 2 components in light water reactor plants as specified in Section III, Division 1 of the ASME Boiler and Pressure Vessel Code, and include the evaluation of primary stress, secondary stress and fatigue damage. However, various new aspects have been incorporated considering the features of superconducting magnet structures. They can be summarized as follows: (i) A new procedure to determine allowable stress intensity value was employed to take advantage of the excellent property of newly developed austenitic stainless steels. (ii) Allowable stress system was simplified considering that only austenitic stainless steels and a nickel-based alloy are planned to be used. (iii) A design fatigue curve at 4K was developed for austenitic stainless steels. (iv) In addition to the conventional fatigue assessment based on design fatigue curves, guidelines for fatigue assessment based on crack growth prediction were added as a non-mandatory appendix to provide a tool of assurance for welded joints which are difficult to evaluate nondestructively during the service.

Comparison Between ASME Code-Case N-761, NUREG/CR-6909 and Stainless Steel Component Fatigue Test Results

2014 ◽  
Author(s):  
H. T. Harrison ◽  
Robert Gurdal
Keyword(s):  
Stainless Steel ◽  
Fatigue Test ◽  
Fatigue Tests ◽  
Test Series ◽  
Test Results ◽  
Actual Number ◽  
Steel Component ◽  
Class 1 ◽  
Asme Code ◽  
Number Of Cycles

For Class 1 components, the consideration of the environmental effects on fatigue has been suggested to be evaluated through two different methodologies: either NUREG/CR-6909 from March 2007 or ASME-Code Case N-761 from August 2010. The purpose of this technical paper is to compare these two methods. In addition, the equations from Revision 1 of the NUREG/CR-6909 will be evaluated. For these comparisons, two stainless steel component fatigue test series with documented results are considered. These two fatigue test series are completely different from each other (applied cyclic displacements vs. insurge/outsurge types of transients). Therefore, they are producing an appropriate foundation for these comparisons. In general, the severities of the two methods are compared, where the severity is defined as the actual number of cycles from the fatigue tests, including an evaluation of the scatter, divided by the number of design cycles from the two methods. Also, how stable the methods are is being evaluated through the calculation of the coefficient of variation for each method.

Proposal of New Upper Limit of Hydrostatic Test Pressure in KT-3 of ASME Section VIII Division 3

2018 ◽  
Author(s):  
Susumu Terada
Keyword(s):  
Test Results ◽  
Design Factor ◽  
Burst Test ◽  
Increase Wall Thickness ◽  
Upper Limit ◽  
General Yielding ◽  
Test Pressure ◽  
Section Viii ◽  
Division 2 ◽  
Design Pressure

The current upper limit of hydrostatic test pressure in KT-3 of ASME Sec. VIII Division 3 is determined by general yielding through the thickness obtained by Nadai’s equation with a design factor of 0.866 (= 1.732/2). On the other hand, the upper limit of hydrostatic test pressure in 4.1.6 of the ASME Sec. VIII Division 2 is determined by general yielding through the thickness with a design factor of 0.95. In cases where a ratio of hydrostatic test pressure to design pressure of 1.43 similar to PED (Pressure Equipment Directive) is requested, the upper limit of hydrostatic test pressure may be critical for vessel design when material with a ratio of yield strength to tensile strength less than 0.7 is used. In order to satisfy the requirements in KT-3, it is necessary to decrease design pressure or increase wall thickness. Therefore, it is proposed to change the design factor of intermediate strength materials to obtain the upper limit of hydrostatic test pressure. In this paper, a new design factor to obtain the upper limit of hydrostatic test pressure is proposed and the validity of this proposal was investigated by burst test results and elastic-plastic analysis.

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