Critical Analysis of the New High Cycle Fatigue Assessment Procedure From ASME B31.3—Appendix W

2021 ◽  
Vol 143 (5) ◽  
Author(s):  
Nikola Jaćimović ◽  
Sondre Luca Helgesen
Keyword(s):  
High Cycle Fatigue ◽  
Design Procedure ◽  
Piping System ◽  
Assessment Procedure ◽  
Stress Range ◽  
Cycle Fatigue ◽  
Fatigue Design ◽  
Process Piping ◽  
Piping Systems ◽  
Fatigue Evaluation

Abstract ASME B31.3, the leading process piping system design code, has included in its 2018 edition a new procedure for evaluation of high cycle fatigue in process piping systems. As stated in the Appendix W of ASME B31.3-2018, this new procedure is applicable to any load resulting in the stress range in excess of 20.7 MPa (3.0 ksi) and with the total number of cycles exceeding 100,000. However, this new procedure is based on the stress range calculation typical to ASME B31 codes which underestimates the realistic expansion stress range by a factor of ∼2. While the allowable stress range used typically for fatigue evaluation of piping systems is adjusted to take into consideration this fact, the new fatigue design curves seem not to take it into account. Moreover, the applicability of the new design procedure (i.e., welded joint fatigue design curves) to the components which tend to fail away from the bends is questionable. Two examples are presented at the end of the paper in order to substantiate the indicated inconsistencies in the verification philosophy.

Proposed ASME Code High Cycle Fatigue Design Curves for Austenitic and Ferritic Steels

2017 ◽  
Author(s):  
Sampath Ranganath ◽  
Hardayal S. Mehta ◽  
Nathan A. Palm ◽  
John Hosler
Keyword(s):  
High Cycle Fatigue ◽  
Ferritic Steels ◽  
Mean Stress ◽  
Cycle Fatigue ◽  
Design Curve ◽  
Fatigue Design ◽  
Asme Code ◽  
The Mean ◽  
Number Of Cycles ◽  
Fatigue Evaluation

The ASME Code fatigue curves (S–N curves) are used in the fatigue evaluation of reactor components. For the assessment of high frequency cyclic loading (such as those produced by flow-induced vibrations), where the number of cycles is expected to be very large and cannot be estimated, the stresses are evaluated by comparison with the fatigue limit1 at 1011 cycles. Other high cycle events of finite time duration (e.g. safety relief loading), where the number of cycles is large but well defined, the fatigue evaluation is performed by comparing the calculated stress with the allowable values defined by the high cycle fatigue design curve. This paper discusses the development of fatigue design curves for austenitic and ferritic steels when the number of cycles is in the range 106 – 1011 cycles. The first part of the paper addresses austenitic stainless steel components which are used for reactor internals. Specifically, the approach described here uses temperature dependent properties (cyclic yield strength, cyclic ultimate strength) for the mean stress correction and the correction for the modulus of elasticity. The high cycle fatigue design curve is developed by applying the mean stress and the E correction on the reversing load mean data curve and applying a factor of 2 on stress. The generic methodology developed for austenitic steel was applied to carbon and low alloy steels also. The proposed fatigue design curves are part of a draft ASME Code Case being considered by the ASME Code Subgroup on Design Methods. This paper describes the technical basis for the proposed ASME Code Case for the high cycle fatigue design curves for austenitic and ferritic steels.

Computer Piping Analysis, ASME B31.3 Appendix S: Example S3 — Moment Reversal

2007 ◽  
Author(s):  
Don R. Edwards
Keyword(s):  
Stress Analysis ◽  
Petroleum Refinery ◽  
Axial Stress ◽  
Piping System ◽  
Stress Range ◽  
Analysis Software ◽  
Process Piping ◽  
Piping Systems ◽  
Operating Stress ◽  
The Impact

The American Standards Association (ASA) B31.3-1959 Petroleum Refinery Piping Code [1] grew out of an ASA document that addressed all manner of fluid conveying piping systems. ASA B31.3 was created long before widespread engineering use of computer “mainframes” or even before the inception of piping stress analysis software. From its inception until recent times, the B31.3 Process Piping Code [2] (hereafter referred to as the “Code”) has remained ambiguous in several areas. This paper describes some of these subtle concepts that are included in the Code 2006 Edition for Appendix S Example S3. This paper discusses: • the effect of moment reversal in determining the largest Displacement Stress Range, • the impact of the average axial stress caused by displacement strains on the Example S3 piping system and the augmenting of the Code Eq. (17) thereto, • a brief comparison of Example S3 results to that of the operating stress range evaluated in accordance with the 2006 Code Appendix P Alternative Requirements.

A Novel High Cycle Fatigue Assessment of Small-Bore Side Branches: Tailor-Made Acceptable Vibration Levels Based on the Remaining Life of Existing Structures

2014 ◽  
Author(s):  
Pieter van Beek ◽  
Richard Pijpers ◽  
Kenneth Macdonald ◽  
Johan Maljaars ◽  
Knud Lunde ◽  
...  
Keyword(s):  
Fracture Mechanics ◽  
High Cycle Fatigue ◽  
Side Branch ◽  
International Standards ◽  
Screening Methods ◽  
Piping System ◽  
Cycle Fatigue ◽  
Fatigue Assessment ◽  
Mechanics Model

In the process systems of offshore installations, welded small-bore side branches can prove vulnerable to high-cycle fatigue failure due to vibrations. This is especially the case for welded connections at tie-in points to the main pipe which are often critical details. International standards and guidelines therefore provide maximum acceptable vibration levels to ensure long term safe operation. In some guidelines, however, these acceptable vibration levels are phrased in terms of screening levels and in practice can be unduly conservative. Process pipework might then unjustly be regarded as unsafe based on measured vibrations in the field. This is especially true for offshore systems, which are characterized by low mechanical damping in the structure. This may result in overdesigned piping or over-conservative operational limits in order to keep vibration levels within the acceptable range. Furthermore, the screening methods and any detailed fatigue assessments typically use established stress-life (S-N) based fatigue design methods where uncertainty exists in the very high-cycle regime. This paper describes a novel and advanced tailor-made fatigue assessment method whereby acceptable vibration levels are based on maximum acceptable stress ranges for individual side branches. The acceptable stress ranges for each critical welded connection are based on a fracture mechanics analysis of fatigue crack growth. This method also minimizes the cantilevered (overhung) mass of small-bore side branches, whilst remaining safe for long-term operation. To illustrate the strength of the assessment methodology in practice, this paper describes the application of the procedure to a 2″ side branch connected to a main piping system. A fracture mechanics model and a detailed 3D finite element model are made. By comparing the stress ranges from the fracture mechanics model with the normalized stress ranges obtained from the dynamic FE analysis, maximum acceptable vibration levels for this particular side branch have been derived. The method is validated with experimental modal analysis and strain gauge measurements.

Computer Based Process Piping Stress Analysis: ASME B31.3 Appendix S — Example S2

2006 ◽  
Author(s):  
Don R. Edwards
Keyword(s):  
Stress Analysis ◽  
Operating Temperature ◽  
Stress Range ◽  
Explicit Equation ◽  
The Past ◽  
Process Piping ◽  
Piping Systems ◽  
Sustained Loads ◽  
Computer Based ◽  
Temperature And Pressure

The American Standards Association (ASA) B31.3-1959 Petroleum Refinery Piping Code [1] grew out of an ASA document that addressed all manner of fluid conveying piping systems. ASA B31.3 was created long before widespread engineering use of computer “mainframes” or even before the inception of piping stress analysis software. Also as B31.3 continued to pass thru standards organizations from ASA, ANSI, to ASME, the B31.3 Process Piping Code [2] (hereafter referred to as the “Code”) has remained ambiguous over the past few decades in several areas. The displacement stress range, SE, has always been explicitly defined by both verbiage and equation. Yet, the sustained condition(s) stress, SL, is mentioned not with an explicit equation but with a statement that the sustained stress shall be limited by the allowable stress at the corresponding operating temperature, Sh. Also one might infer from the vague verbiage in the Code that there is only one sustained condition; this would also be an incorrect inference. Also, assumptions would then have to be made as to which supports are allowed to be included in a sustained analysis based on whether the piping “lifts-off” any of the pipe supports during the corresponding operating condition. This paper describes the subtle yet possibly radical concepts that are included in the (recently approved for inclusion into) ASME B31.3-2006 Appendix S Example S2. This paper discusses: • when and in what manner the most severe set of operating temperature and pressure is to be used; • the concept of “sustained condition” and multiple “anticipated” sustained conditions; • determining the support scenario(s) for each anticipated sustained condition; • establishing the most severe sustained condition to evaluate and determine the stress due to sustained loads, SL; • utilizing an equation with sustained stress indices to evaluate SL; • establishing the least severe sustained condition and its effect in determining the largest displacement stress range, SE.

Pipe Elbows Under Strong Cyclic Loading

2012 ◽  
Vol 135 (1) ◽  
Author(s):  
George E. Varelis ◽  
Spyros A. Karamanos ◽  
Arnold M. Gresnigt
Keyword(s):  
Cyclic Loading ◽  
Low Cycle Fatigue ◽  
Seismic Loading ◽  
Fatigue Curve ◽  
Design Codes ◽  
Loading Conditions ◽  
Cycle Fatigue ◽  
Finite Element Analyses ◽  
Fatigue Design ◽  
Process Piping

Motivated by the response of industrial piping under seismic loading conditions, the present study examines the behavior of steel process piping elbows, subjected to strong cyclic loading conditions. A set of experiments is conducted on elbow specimens subjected to constant amplitude in-plane cyclic bending, resulting into failure in the low-cycle-fatigue range. The experimental results are used to develop a low-cycle-fatigue curve within the strain-based fatigue design framework. The experimental work is supported by finite element analyses, which account for geometrical and material nonlinearities. Using advanced plasticity models to describe the behavior of elbow material, the analysis focuses on localized deformations at the critical positions where cracking occurs. Finally, the relevant provisions of design codes (ASME B31.3 and EN 13480) for elbow design are discussed and assessed, with respect to the experimental and numerical findings.

Design Curves for High-Cycle Fatigue Loaded Structural Elements

2013 ◽  
Vol 752 ◽  
pp. 135-144 ◽  
Author(s):  
Zsuzsanna Koncsik ◽  
János Lukács
Keyword(s):  
High Cycle Fatigue ◽  
Empirical Method ◽  
Fatigue Tests ◽  
Structural Elements ◽  
Cycle Fatigue ◽  
Structural Element ◽  
Fatigue Design ◽  
Structural Details ◽  
Important Design

Frequently, the cause of the failure of different structures or structural elements is the cyclic loading. Both fatigue design curves and methods for determination of these curves can be found in the literature. Even so, there are structural details whereabouts executing of examinations is necessary. The aims of the study are as follows: to give a short summary of important design curves can be found in different standards or specifications; and to demonstrate of own high cycle fatigue tests on a soldered structural element and the comparing of our results and the results of an empirical method.

Dynamic Support in Piping Systems: A Novel Design Based on Automotive Shock Absorbers

2003 ◽  
Author(s):  
Roman W. Motriuk ◽  
Edwin Mikulcik
Keyword(s):  
Design Procedure ◽  
Piping System ◽  
Test Procedures ◽  
Support Design ◽  
Response Characteristics ◽  
Shock Absorbers ◽  
Lack Of Information ◽  
Piping Systems ◽  
Dynamic Support ◽  
Novel Design

Complex vibration fields are observed in piping systems that are mechanically or acoustically interconnected with turbo-machinery. The magnitudes of vibrations in such systems depend on the coupling of the piping response characteristics with the excitations that are present. In cases of high vibration amplitudes, successful mechanical attenuation can be achieved by altering the piping system’s mass or its stiffness, thus detuning the piping response from the excitation. Another approach is to introduce damping into the piping system so that the vibration energy can be efficiently dissipated, hence mitigating unacceptable vibration amplitudes. All of the above principles are used successfully across the industry. This paper describes a novel support design that has been used successfully to solve vibration problems in cases such as those described above. This device was initially conceived as being a very economical solution for simply adding damping to reduce the vibration amplitude. Its economy is derived from being based on the use of standard automotive or truck-type shock absorbers, which were expected to be very effective in providing damping because of their success in automotive applications. The device which was designed is lightweight and therefore very versatile in the manner in which it can be deployed, such that anchoring and attachment requirements can be very simple, thus accommodating space or foundation necessities that could be problematic using more standard approaches. Because of the lack of information existing on the damping properties of such shock absorbers, the first design was implemented on a trial-and-error basis. However, its success motivated further investigations into the characteristics of shock absorbers, so that the initial installation could be evaluated through a more proper analysis and lead to a more general design procedure for other applications. Extensive laboratory tests were done using several different shock absorbers to gain an insight into their characteristics when used in the manner required here. The test procedures and the data from these tests are described in this paper, together with the analysis of the successful installation. It was found, unexpectedly, that the shock absorbers contribute significantly in both damping and stiffness, thus providing a powerful combination of detuning as well as damping when used in this way. This paper demonstrates a general approach to the techniques of testing and the design of similar such systems.

High-Cycle Fatigue Design Evolution and Experience of Free-Standing Combustion Turbine Blades

1992 ◽  
Vol 114 (2) ◽  
pp. 284-292 ◽  
Author(s):  
A. J. Scalzo
Keyword(s):  
Turbine Blade ◽  
High Cycle Fatigue ◽  
Turbine Blades ◽  
Design Criteria ◽  
Cycle Fatigue ◽  
Free Standing ◽  
Fatigue Design ◽  
Turbine Blade Design ◽  
Westinghouse Electric ◽  
Cooling Air

Combustion turbine blade design criteria can generally be classified as either temperature or fatigue related. Since less is usually known about the factors influencing the fatigue phenomenon, it is considered the more challenging. In addition, as analytical and experimental techniques became more sophisticated and more accurate, the natural tendency was to replace archaic “guidelines” or “rules” with less conservative approaches that at times led to the discovery of new high-cycle fatigue “thresholds.” This paper presents the evolution of the combustion turbine blade high cycle fatigue design criteria for free-standing blades. It also presents the analysis and corrective actions taken to resolve several unique combustion turbine blade fatigue problems, all encountered over a 35-year period while the author has been employed at Westinghouse Electric Corporation. Included are high-cycle fatigue problems due to cooling air leakage, seal pin friction, and combustion temperature maldistribution, as well as flow-induced nonsynchronous vibration.

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