Assessment method for complex cracked pipe using equivalent pipe concept

Kyung Dong Bae, Ho Wan Ryu, Seung Jae Kim, Hyun Suk Nam, Yun Jae Kim

研究成果: Conference contribution

抄録

This paper proposes the assessment method of complex cracked pipes. Complex crack is the form of crack existing through-wall crack and surface crack at the same time [1-2]. Complex crack is mainly caused by PWSCC phenomenon in pipe with overlay maintenance welding. At first, circumferential surface crack is developed by PWSCC phenomenon in the weakest point which is nickel alloy welding point. And this crack propagates to axisymmetric crack in inner surface. After that the crack initiates in not only pipe part but also overlay maintenance welding part, complex crack shape which is main subject in this paper is formed. Unlike throughwall cracked pipes or surface cracked pipes, complex cracked pipes have a complex behavior because of combining throughwall crack behaviors and surface crack behaviors in cracked part. So calculating J-integral and defining amount of crack growth of complex cracked pipes are more difficult than those of through-wall cracked pipes and surface cracked pipes. Therefore, in this paper, the concept using equivalent pipe is proposed for assessment method of complex cracked pipes. To determine equivalent pipe, maximum loads of various throughwall cracked pipes having same circumferential crack size and different thickness are calculated. The reason why through-wall cracked pipe is selected for equivalent pipe is that many researches about J-integral and crack growth of through-wall cracked pipes are already performed and those results are sufficiently validated. In addition, it can be not only directly utilized procedure of leak before break assessment but also compared previous research results using only through-wall cracked part in complex cracked pipes referred to reduced thickness method. Maximum loads of complex cracked pipes and through-wall cracked pipes are calculated using stressmodified fracture strain model in finite element analysis [3-6]. This model is technics removing load bearing capacity in elements which satisfy damage criteria. Damage criteria is determined by using tensile experiment results, fracture toughness experiment results and validated by comparing with real size pipe experiment results. All the experiment results are in pipe fracture encyclopedia published by Battelle [7]. The experiments utilized in the paper are performed in operating temperature 288°C and materials of pipes are stainless steel SA376 TP304 and carbon steel A106 Gr.B. Finally, the results of equivalent through-wall cracked pipe thickness are provided.

本文言語English
ホスト出版物のタイトルMaterials and Fabrication
出版社American Society of Mechanical Engineers (ASME)
ISBN(電子版)9780791850428
DOI
出版ステータスPublished - 2016
外部発表はい
イベントASME 2016 Pressure Vessels and Piping Conference, PVP 2016 - Vancouver, Canada
継続期間: 2016 7 172016 7 21

出版物シリーズ

名前American Society of Mechanical Engineers, Pressure Vessels and Piping Division (Publication) PVP
6A-2016
ISSN(印刷版)0277-027X

Conference

ConferenceASME 2016 Pressure Vessels and Piping Conference, PVP 2016
国/地域Canada
CityVancouver
Period16/7/1716/7/21

ASJC Scopus subject areas

  • 機械工学

フィンガープリント

「Assessment method for complex cracked pipe using equivalent pipe concept」の研究トピックを掘り下げます。これらがまとまってユニークなフィンガープリントを構成します。

引用スタイル