Evaluation and interpretation of ductile crack extension in SENT specimens using unloading compliance technique

Abstract Resistance curves obtained from Single Edge Notch Tensile (SENT) specimens gain interest for defect assessment in pipelines. To determine these resistance curves, the unloading compliance technique is a commonly applied single specimen technique. A frequently reported problem is the occurrence of an initial decrease in the compliance, resulting in an apparent negative crack growth. To overcome this problem an offset in combination with a blunting correction is proposed. This approach is evaluated by finite element simulations. Then the proposed approach is validated experimentally. The presented approach is simple in use and provides an acceptable estimation error when it comes to constructing resistance curves.

[1]  J. E. Perez Ipiña,et al.  Mechanical Properties Degradation at Room Temperature in ZRY-4 by Hydrogen Brittleness , 2002 .

[2]  John D. Landes,et al.  THE BLUNTING LINE IN ELASTIC‐PLASTIC FRACTURE , 1995 .

[3]  H. Pisarski,et al.  Determination of Pipe Girth Weld Fracture Toughness Using Sent Specimens , 2010 .

[4]  R. E. Link,et al.  Crack Size Evaluation Using Unloading Compliance in Single-Specimen Single-Edge-Notched Tension Fracture Toughness Testing , 2009 .

[5]  W. R. Tyson,et al.  J-Resistance Results From Multi-Specimen and Single-Specimen Surface Notched SEN(T) Geometry , 2012 .

[6]  A Wolfenden,et al.  JIc Data Analysis Methods with a “Negative Crack Growth” Correction Procedure , 1990 .

[7]  Nader Yoosef-Ghodsi,et al.  Finite Element Analysis of Flaw Growth History , 2010 .

[8]  A. Kifani,et al.  The effect of notch radius on fracture toughness JIc , 2000 .

[9]  Yaxin Song,et al.  Multi-Tier Tensile Strain Models for Strain-Based Design: Part 2 — Development and Formulation of Tensile Strain Capacity Models , 2012 .

[10]  D. W. Zhou.  Measurement and modelling of R-curves for low-constraint specimens , 2011 .

[11]  Mario L. Macia,et al.  Development of the SENT Test for Strain-Based Design of Welded Pipelines , 2010 .

[12]  Joe Zhou,et al.  Modeling and CMOD Mapping of Surface-Cracked Wide Plates , 2008 .

[13]  Ming Liu,et al.  Multi-Tier Tensile Strain Models for Strain-Based Design: Part 1 — Fundamental Basis , 2012 .

[14]  Mario L. Macia,et al.  A Multi-Tiered Procedure For Engineering Critical Assessment of Strain-Based Pipelines , 2011 .

[15]  Jeffrey W. Sowards,et al.  SE(T) Testing of Pipeline Welds , 2010 .

[16]  Karel Minnaar,et al.  Characterization of the Stable Tearing During Pipeline Strain Capacity Tests , 2008 .

[17]  Chang-Sung Seok.  Correction methods of an apparent negative crack growth phenomenon , 2000 .

[18]  Wenxing Zhou,et al.  An Experimental Study on J(CTOD)-R Curves of Single Edge Tension Specimens for X80 Steel , 2012 .

[19]  B. K. Neale.  The fracture behaviour of mismatched centre-cracked welded specimens in tension , 1999 .

[20]  Claudio Ruggieri,et al.  Estimation procedure of J-resistance curves for SE(T) fracture specimens using unloading compliance , 2007 .

[21]  Robert H. Dodds,et al.  Numerical investigation of 3-D constraint effects on brittle fracture in SE(B) and C(T) specimens , 1996 .

[22]  J. Rice.  A path-independent integral and the approximate analysis of strain , 1968 .

[23]  James A. Gianetto,et al.  Measurement of J-R Curves Using Single-Specimen Technique On Clamped SE(T) Specimens , 2009 .

[24]  B. K. Neale.  The fracture toughness testing of centre-cracked tensile specimens using the unloading compliance technique , 1998 .

[25]  Leif Collberg,et al.  Introduction to the Update of DNV'96, DNV OS F101; Submarine Pipeline Systems , 1999 .

[26]  James A. Gianetto,et al.  Evaluation of Fracture Toughness of X100 Pipe Steel Using SE(B) and Clamped SE(T) Single Specimens , 2010 .

[27]  Rudi Denys,et al.  Measurement of ductile crack extension in single edge notch tensile specimens , 2012 .

[28]  Stijn Hertelé,et al.  Curved Wide Plate Testing With Advanced Instrumentation and Interpretation , 2012 .

[29]  K. P. Weiss,et al.  Specific aspects on crack advance during J-test method for structural materials at cryogenic temperatures , 2006 .

[30]  Claudio Ruggieri,et al.  Correlation of fracture behavior in high pressure pipelines with axial flaws using constraint designed test specimens––Part I: Plane-strain analyses , 2005 .

[31]  Rudi Denys,et al.  Strain capacity prediction for strain-based pipeline designs , 2013 .

[32]  Bård Nyhus,et al.  Constraint correction of high strength steel Selection of test specimens and application of direct calculations , 2004 .

[33]  Y. Ling,et al.  Uniaxial True Stress-Strain after Necking , 2004 .