A strain gauge method for detecting ductile crack initiation

1978 ◽  
Vol 14 (4) ◽  
pp. R199-R204 ◽  
Author(s):  
M. S. Kamath ◽  
M. J. Neaves
Keyword(s):  
Crack Initiation ◽  
Strain Gauge ◽  
Ductile Crack

Design of crack arrestors for ultra high grade gas transmission pipelines: simulation of crack initiation, propagation and arrest

2011 ◽  
Vol 2 (2) ◽  
pp. 307-319
Author(s):  
F. Van den Abeele ◽  
M. Di Biagio ◽  
L. Amlung
Keyword(s):  
Crack Initiation ◽  
Crack Propagation ◽  
Large Scale ◽  
Large Diameter ◽  
Pipe Material ◽  
High Grade ◽  
Gas Pipelines ◽  
Ductile Crack ◽  
Reinforced Plastics ◽  
Four Point Bending

One of the major challenges in the design of ultra high grade (X100) gas pipelines is the identification of areliable crack propagation strategy. Recent research results have shown that the newly developed highstrength and large diameter gas pipelines, when operated at severe conditions, may not be able to arrest arunning ductile crack through pipe material properties. Hence, the use of crack arrestors is required in thedesign of safe and reliable pipeline systems.A conventional crack arrestor can be a high toughness pipe insert, or a local joint with higher wall thickness.According to experimental results of full-scale burst tests, composite crack arrestors are one of the mostpromising technologies. Such crack arrestors are made of fibre reinforced plastics which provide the pipewith an additional hoop constraint. In this paper, numerical tools to simulate crack initiation, propagationand arrest in composite crack arrestors are introduced.First, the in-use behaviour of composite crack arrestors is evaluated by means of large scale tensile testsand four point bending experiments. The ability of different stress based orthotropic failure measures topredict the onset of material degradation is compared. Then, computational fracture mechanics is applied tosimulate ductile crack propagation in high pressure gas pipelines, and the corresponding crack growth inthe composite arrestor. The combination of numerical simulation and experimental research allows derivingdesign guidelines for composite crack arrestors.

scholarly journals Energy dissipation via acoustic emission in ductile crack initiation

2016 ◽  
Vol 199 (1) ◽  
pp. 89-104 ◽  
Author(s):  
J. A. Cuadra ◽  
K. P. Baxevanakis ◽  
M. Mazzotti ◽  
I. Bartoli ◽  
A. Kontsos
Keyword(s):  
Acoustic Emission ◽  
Energy Dissipation ◽  
Crack Initiation ◽  
Ductile Crack

scholarly journals Evaluation of ductile crack initiation limit using strain hardening exponent

2016 ◽  
Vol 82 (842) ◽  
pp. 16-00096-16-00096
Author(s):  
Takehisa YAMADA ◽  
Yoichi YAMASHITA ◽  
Sohei KANNA
Keyword(s):  
Crack Initiation ◽  
Strain Hardening ◽  
Strain Hardening Exponent ◽  
Ductile Crack

Simulation of Ductile Tearing in a Dissimilar Material Weld up to Pipe Wall Break-Through

2010 ◽  
Author(s):  
Philippe Gilles ◽  
Alexandre Brosse ◽  
Moi¨se Pignol
Keyword(s):  
Crack Initiation ◽  
Crack Growth ◽  
Wall Thickness ◽  
Surface Crack ◽  
Pipe Wall ◽  
Ductile Crack ◽  
Pipe Wall Thickness ◽  
Ductile Tearing ◽  
Ductile Crack Growth ◽  
Computational Analyses

This paper presents ductile initiation calculations and growth simulations of a surface crack up to pipe wall breakthrough. For validation purpose, one of the two BIMET configurations is selected. The EC program BIMET has been carried out to analyze the ductile tearing behavior of DMWs through experiments and computational analyses. In the mock-up, the initial defect is an external circumferential defect located close to the weld-ferritic interface, with a depth of one third of the wall thickness. During the test, the crack extended up to two third of the pipe wall thickness. The aim of the study is to simulate the crack initiation and growth, to compare the results with the experimental records and to continue the ductile crack growth up to pipe wall break-through.

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