Dynamic behaviour of pipelines in power plants

Research output: Chapter in Book/Report/Conference proceedingConference article in proceedingsScientific

Abstract

Dynamic excitation due to a pipe break can cause pipe to abruptly displace and hit the components, instrumentation and equipment nearby. In order to minimize the risk of such damage by pipe whips in a power plant, different types of restraints and supports are designed for the pipelines. The usability of different types of elements provided by Abaqus, a commercial general-purpose finite element code, in modelling the dynamic behaviour of pipelines is tested. A relatively short pipe line section with one bend and one restraint is chosen as a test case. Simple and typical nuclear power plant pipeline geometry and materials are chosen. The stiffness of the restraint as well as the flexural stiffness of the pipe cross-section are solved with static compression simulations with a detailed model using three-dimensional solid and shell elements. After that, the model is substituted with couple of simpler models using pipe and/or elbow elements for the pipe and a spring element for the restraint. The eigenmodes of models are calculated and compared with each other. The pipe whip is simulated with nonlinear dynamic analyses with the most adequate models according to the preliminary linear analyses. The displacement and stress results of different models are compared with each other and the reliability and adequacy of different element types are discussed. Sensitivity study is made by varying analysis type, material properties, mesh density, element properties and inner pressure. The results of the most adequate simple models with the right combinations of special-purpose elements provided by Abaqus corresponded well to the ones of the much larger three-dimensional solid and shell element models. The post-yield behaviour of the pipe steel material has some notable effect on the behaviour of the pipe in a guillotine pipe break. Obviously, rate dependence makes the structure slightly dynamically stiffer. The inner pressure of the pipe and its assumed decay after the pipe break has a major influence on the results. It is shown, how the stress distribution along the pipe axis, around the cross-section and through the thickness of the wall can be solved with elbow elements on a fairly detailed level. Long pipe runs with many supports and restraints should preferably be modelled with simple structural elements such as pipe and elbow elements and special-purpose elements in order to save time and numerical errors due to overly large models.
Original languageEnglish
Title of host publicationBaltica VIII
Subtitle of host publicationLife Management and Maintenance for Power Plants
Place of PublicationEspoo
PublisherVTT Technical Research Centre of Finland
Pages113-125
Volume1
ISBN (Electronic)978-951-38-7592-3
ISBN (Print)978-951-38-7591-6
Publication statusPublished - 2010
MoE publication typeB3 Non-refereed article in conference proceedings
EventBALTICA VIII - International Conference on Life Management and Maintenance for Power Plants - Helsinki-Stockholm, Finland
Duration: 18 May 201020 May 2010

Publication series

SeriesVTT Symposium
Number264
ISSN0357-9387

Conference

ConferenceBALTICA VIII - International Conference on Life Management and Maintenance for Power Plants
CountryFinland
CityHelsinki-Stockholm
Period18/05/1020/05/10

Fingerprint

Power plants
Pipelines
Pipe
Stiffness
Steel pipe
Nuclear power plants
Stress concentration
Materials properties

Cite this

Calonius, K. (2010). Dynamic behaviour of pipelines in power plants. In Baltica VIII: Life Management and Maintenance for Power Plants (Vol. 1, pp. 113-125). Espoo: VTT Technical Research Centre of Finland. VTT Symposium, No. 264
Calonius, Kim. / Dynamic behaviour of pipelines in power plants. Baltica VIII: Life Management and Maintenance for Power Plants. Vol. 1 Espoo : VTT Technical Research Centre of Finland, 2010. pp. 113-125 (VTT Symposium; No. 264).
@inproceedings{2d5b946fd74e4755acf6715e05d06343,
title = "Dynamic behaviour of pipelines in power plants",
abstract = "Dynamic excitation due to a pipe break can cause pipe to abruptly displace and hit the components, instrumentation and equipment nearby. In order to minimize the risk of such damage by pipe whips in a power plant, different types of restraints and supports are designed for the pipelines. The usability of different types of elements provided by Abaqus, a commercial general-purpose finite element code, in modelling the dynamic behaviour of pipelines is tested. A relatively short pipe line section with one bend and one restraint is chosen as a test case. Simple and typical nuclear power plant pipeline geometry and materials are chosen. The stiffness of the restraint as well as the flexural stiffness of the pipe cross-section are solved with static compression simulations with a detailed model using three-dimensional solid and shell elements. After that, the model is substituted with couple of simpler models using pipe and/or elbow elements for the pipe and a spring element for the restraint. The eigenmodes of models are calculated and compared with each other. The pipe whip is simulated with nonlinear dynamic analyses with the most adequate models according to the preliminary linear analyses. The displacement and stress results of different models are compared with each other and the reliability and adequacy of different element types are discussed. Sensitivity study is made by varying analysis type, material properties, mesh density, element properties and inner pressure. The results of the most adequate simple models with the right combinations of special-purpose elements provided by Abaqus corresponded well to the ones of the much larger three-dimensional solid and shell element models. The post-yield behaviour of the pipe steel material has some notable effect on the behaviour of the pipe in a guillotine pipe break. Obviously, rate dependence makes the structure slightly dynamically stiffer. The inner pressure of the pipe and its assumed decay after the pipe break has a major influence on the results. It is shown, how the stress distribution along the pipe axis, around the cross-section and through the thickness of the wall can be solved with elbow elements on a fairly detailed level. Long pipe runs with many supports and restraints should preferably be modelled with simple structural elements such as pipe and elbow elements and special-purpose elements in order to save time and numerical errors due to overly large models.",
author = "Kim Calonius",
year = "2010",
language = "English",
isbn = "978-951-38-7591-6",
volume = "1",
series = "VTT Symposium",
publisher = "VTT Technical Research Centre of Finland",
number = "264",
pages = "113--125",
booktitle = "Baltica VIII",
address = "Finland",

}

Calonius, K 2010, Dynamic behaviour of pipelines in power plants. in Baltica VIII: Life Management and Maintenance for Power Plants. vol. 1, VTT Technical Research Centre of Finland, Espoo, VTT Symposium, no. 264, pp. 113-125, BALTICA VIII - International Conference on Life Management and Maintenance for Power Plants, Helsinki-Stockholm, Finland, 18/05/10.

Dynamic behaviour of pipelines in power plants. / Calonius, Kim.

Baltica VIII: Life Management and Maintenance for Power Plants. Vol. 1 Espoo : VTT Technical Research Centre of Finland, 2010. p. 113-125 (VTT Symposium; No. 264).

Research output: Chapter in Book/Report/Conference proceedingConference article in proceedingsScientific

TY - GEN

T1 - Dynamic behaviour of pipelines in power plants

AU - Calonius, Kim

PY - 2010

Y1 - 2010

N2 - Dynamic excitation due to a pipe break can cause pipe to abruptly displace and hit the components, instrumentation and equipment nearby. In order to minimize the risk of such damage by pipe whips in a power plant, different types of restraints and supports are designed for the pipelines. The usability of different types of elements provided by Abaqus, a commercial general-purpose finite element code, in modelling the dynamic behaviour of pipelines is tested. A relatively short pipe line section with one bend and one restraint is chosen as a test case. Simple and typical nuclear power plant pipeline geometry and materials are chosen. The stiffness of the restraint as well as the flexural stiffness of the pipe cross-section are solved with static compression simulations with a detailed model using three-dimensional solid and shell elements. After that, the model is substituted with couple of simpler models using pipe and/or elbow elements for the pipe and a spring element for the restraint. The eigenmodes of models are calculated and compared with each other. The pipe whip is simulated with nonlinear dynamic analyses with the most adequate models according to the preliminary linear analyses. The displacement and stress results of different models are compared with each other and the reliability and adequacy of different element types are discussed. Sensitivity study is made by varying analysis type, material properties, mesh density, element properties and inner pressure. The results of the most adequate simple models with the right combinations of special-purpose elements provided by Abaqus corresponded well to the ones of the much larger three-dimensional solid and shell element models. The post-yield behaviour of the pipe steel material has some notable effect on the behaviour of the pipe in a guillotine pipe break. Obviously, rate dependence makes the structure slightly dynamically stiffer. The inner pressure of the pipe and its assumed decay after the pipe break has a major influence on the results. It is shown, how the stress distribution along the pipe axis, around the cross-section and through the thickness of the wall can be solved with elbow elements on a fairly detailed level. Long pipe runs with many supports and restraints should preferably be modelled with simple structural elements such as pipe and elbow elements and special-purpose elements in order to save time and numerical errors due to overly large models.

AB - Dynamic excitation due to a pipe break can cause pipe to abruptly displace and hit the components, instrumentation and equipment nearby. In order to minimize the risk of such damage by pipe whips in a power plant, different types of restraints and supports are designed for the pipelines. The usability of different types of elements provided by Abaqus, a commercial general-purpose finite element code, in modelling the dynamic behaviour of pipelines is tested. A relatively short pipe line section with one bend and one restraint is chosen as a test case. Simple and typical nuclear power plant pipeline geometry and materials are chosen. The stiffness of the restraint as well as the flexural stiffness of the pipe cross-section are solved with static compression simulations with a detailed model using three-dimensional solid and shell elements. After that, the model is substituted with couple of simpler models using pipe and/or elbow elements for the pipe and a spring element for the restraint. The eigenmodes of models are calculated and compared with each other. The pipe whip is simulated with nonlinear dynamic analyses with the most adequate models according to the preliminary linear analyses. The displacement and stress results of different models are compared with each other and the reliability and adequacy of different element types are discussed. Sensitivity study is made by varying analysis type, material properties, mesh density, element properties and inner pressure. The results of the most adequate simple models with the right combinations of special-purpose elements provided by Abaqus corresponded well to the ones of the much larger three-dimensional solid and shell element models. The post-yield behaviour of the pipe steel material has some notable effect on the behaviour of the pipe in a guillotine pipe break. Obviously, rate dependence makes the structure slightly dynamically stiffer. The inner pressure of the pipe and its assumed decay after the pipe break has a major influence on the results. It is shown, how the stress distribution along the pipe axis, around the cross-section and through the thickness of the wall can be solved with elbow elements on a fairly detailed level. Long pipe runs with many supports and restraints should preferably be modelled with simple structural elements such as pipe and elbow elements and special-purpose elements in order to save time and numerical errors due to overly large models.

M3 - Conference article in proceedings

SN - 978-951-38-7591-6

VL - 1

T3 - VTT Symposium

SP - 113

EP - 125

BT - Baltica VIII

PB - VTT Technical Research Centre of Finland

CY - Espoo

ER -

Calonius K. Dynamic behaviour of pipelines in power plants. In Baltica VIII: Life Management and Maintenance for Power Plants. Vol. 1. Espoo: VTT Technical Research Centre of Finland. 2010. p. 113-125. (VTT Symposium; No. 264).