Study and Methodology Development for Cyclic Loading Application to Fatigue Analyses

Research output: Contribution to conferenceConference articleScientific

Abstract

This study concerns collection, review and development of cyclic loading methods applicable to probabilistic fatigue induced crack growth analyses. These approaches are applicable to nuclear power plant (NPP) piping components.
The main characteristics of cyclic loading are the frequency of occurrence and the amplitude. Both of these can remain constant or vary, the latter option describing much more realistically actual cyclic loading conditions than the former. There are several cases of cyclic loading with locally highly varying frequency of occurrence and amplitude. This is typical for such NPP piping Tees, where turbulent mixing of two water flows having different temperatures occurs. Such high-cycle loading conditions with substantially varying temperatures call for probabilistic more realistic method for application of loading, instead of applying such conservative application methods where some severe constant frequency of occurrence and amplitude are assumed. The use of such computationally simpler and more straightforward methods leads to unrealistically short fatigue crack growth lifetimes. The scope of this study mainly concerns thermal high-cycle loading. This study covers and reviews the most relevant application methods for cyclic thermal loading given in codes and rules of a number of countries using nuclear energy, as well as most promising methods found from fitness-for-service procedures and scientific literature. The developed new application method for cyclic loading is compared to a corresponding existing one in a computational example concerning fatigue induced crack growth in a representative NPP piping Tee. To obtain a more distinctive model response, moderately exaggerated loading was used. The computational fatigue crack growth analysis results show that the new method is considerably less over conservative than the SIN-Method.
Original languageEnglish
Pages45-56
Number of pages12
Publication statusPublished - 30 Sep 2015
MoE publication typeNot Eligible
EventFourth International Conference on Fatigue of Nuclear Reactor Components - Hotel Barcelo, Sevilla, Spain
Duration: 28 Sep 20151 Oct 2015
Conference number: 4

Conference

ConferenceFourth International Conference on Fatigue of Nuclear Reactor Components
CountrySpain
CitySevilla
Period28/09/151/10/15

Fingerprint

Fatigue of materials
Nuclear power plants
Fatigue crack propagation
Crack propagation
Nuclear energy
Temperature
Water
Hot Temperature

Cite this

Cronvall, O. (2015). Study and Methodology Development for Cyclic Loading Application to Fatigue Analyses. 45-56. Paper presented at Fourth International Conference on Fatigue of Nuclear Reactor Components, Sevilla, Spain.
Cronvall, Otso. / Study and Methodology Development for Cyclic Loading Application to Fatigue Analyses. Paper presented at Fourth International Conference on Fatigue of Nuclear Reactor Components, Sevilla, Spain.12 p.
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abstract = "This study concerns collection, review and development of cyclic loading methods applicable to probabilistic fatigue induced crack growth analyses. These approaches are applicable to nuclear power plant (NPP) piping components. The main characteristics of cyclic loading are the frequency of occurrence and the amplitude. Both of these can remain constant or vary, the latter option describing much more realistically actual cyclic loading conditions than the former. There are several cases of cyclic loading with locally highly varying frequency of occurrence and amplitude. This is typical for such NPP piping Tees, where turbulent mixing of two water flows having different temperatures occurs. Such high-cycle loading conditions with substantially varying temperatures call for probabilistic more realistic method for application of loading, instead of applying such conservative application methods where some severe constant frequency of occurrence and amplitude are assumed. The use of such computationally simpler and more straightforward methods leads to unrealistically short fatigue crack growth lifetimes. The scope of this study mainly concerns thermal high-cycle loading. This study covers and reviews the most relevant application methods for cyclic thermal loading given in codes and rules of a number of countries using nuclear energy, as well as most promising methods found from fitness-for-service procedures and scientific literature. The developed new application method for cyclic loading is compared to a corresponding existing one in a computational example concerning fatigue induced crack growth in a representative NPP piping Tee. To obtain a more distinctive model response, moderately exaggerated loading was used. The computational fatigue crack growth analysis results show that the new method is considerably less over conservative than the SIN-Method.",
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year = "2015",
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language = "English",
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note = "Fourth International Conference on Fatigue of Nuclear Reactor Components ; Conference date: 28-09-2015 Through 01-10-2015",

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Cronvall, O 2015, 'Study and Methodology Development for Cyclic Loading Application to Fatigue Analyses' Paper presented at Fourth International Conference on Fatigue of Nuclear Reactor Components, Sevilla, Spain, 28/09/15 - 1/10/15, pp. 45-56.

Study and Methodology Development for Cyclic Loading Application to Fatigue Analyses. / Cronvall, Otso.

2015. 45-56 Paper presented at Fourth International Conference on Fatigue of Nuclear Reactor Components, Sevilla, Spain.

Research output: Contribution to conferenceConference articleScientific

TY - CONF

T1 - Study and Methodology Development for Cyclic Loading Application to Fatigue Analyses

AU - Cronvall, Otso

PY - 2015/9/30

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AB - This study concerns collection, review and development of cyclic loading methods applicable to probabilistic fatigue induced crack growth analyses. These approaches are applicable to nuclear power plant (NPP) piping components. The main characteristics of cyclic loading are the frequency of occurrence and the amplitude. Both of these can remain constant or vary, the latter option describing much more realistically actual cyclic loading conditions than the former. There are several cases of cyclic loading with locally highly varying frequency of occurrence and amplitude. This is typical for such NPP piping Tees, where turbulent mixing of two water flows having different temperatures occurs. Such high-cycle loading conditions with substantially varying temperatures call for probabilistic more realistic method for application of loading, instead of applying such conservative application methods where some severe constant frequency of occurrence and amplitude are assumed. The use of such computationally simpler and more straightforward methods leads to unrealistically short fatigue crack growth lifetimes. The scope of this study mainly concerns thermal high-cycle loading. This study covers and reviews the most relevant application methods for cyclic thermal loading given in codes and rules of a number of countries using nuclear energy, as well as most promising methods found from fitness-for-service procedures and scientific literature. The developed new application method for cyclic loading is compared to a corresponding existing one in a computational example concerning fatigue induced crack growth in a representative NPP piping Tee. To obtain a more distinctive model response, moderately exaggerated loading was used. The computational fatigue crack growth analysis results show that the new method is considerably less over conservative than the SIN-Method.

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Cronvall O. Study and Methodology Development for Cyclic Loading Application to Fatigue Analyses. 2015. Paper presented at Fourth International Conference on Fatigue of Nuclear Reactor Components, Sevilla, Spain.