Crack Size Evaluation Using Unloading Compliance in Single-Specimen Single-Edge-Notched Tension Fracture Toughness Testing

2009 ◽  
Vol 37 (4) ◽  
pp. 102368 ◽  
Author(s):  
M. R. Mitchell ◽  
R. E. Link ◽  
G. Shen ◽  
W. R. Tyson
Keyword(s):  
Fracture Toughness ◽  
Crack Size ◽  
Single Specimen ◽  
Single Edge ◽  
Fracture Toughness Testing ◽  
Toughness Testing ◽  
Unloading Compliance ◽  
Size Evaluation ◽  
Tension Fracture

Standardization of SENT (or SE(T)) Fracture Toughness Measurement: Results of a Round Robin on a Draft Test Procedure

2016 ◽  
Author(s):  
Sanjay Tiku ◽  
Nick Pussegoda ◽  
Morvarid Ghovanlou ◽  
W. R. Tyson ◽  
Aaron Dinovitzer
Keyword(s):  
Fracture Toughness ◽  
Test Procedure ◽  
Potential Drop ◽  
Round Robin ◽  
Single Specimen ◽  
Test Program ◽  
Round Robin Test ◽  
Fracture Toughness Testing ◽  
Growth Measurement ◽  
Toughness Testing

Fracture toughness of steels is conventionally measured using bend specimens and provides a conservative estimate of toughness when the actual loading is in tension. There has been widespread interest in characterizing the toughness that occurs with reduced constraint to better reflect constraint conditions typical of a relatively shallow girth weld flaw. There is currently a standardized approach to measure fracture toughness in tension loaded specimens, however, it requires testing of multiple specimens to generate a resistance curve. Recent developments in fracture toughness testing and analysis of tension loaded specimens have led to publications by CANMET and Exxon Mobil Upstream Research Company toward development of a single-specimen procedure. As part of an initiative to enhance the state of the art in strain based design and assessment methods, with the intent of providing support for the standardization of appropriate weld testing methods, BMT under a Pipeline research Council International (PRCI) project has combined the two single-specimen approaches and developed a recommended practice for fracture toughness testing using single-edge-notched tension SENT (or SE(T)) samples with fixed grip loading. The procedure has been assessed by means of a round robin test program involving laboratories from around the world. Girth welds were fabricated and base metal, heat affected zone and weld center line specimens were prepared and sent to round robin participants. For the round robin program all the participants used a double clip gauge arrangement for direct CTOD measurement and electric potential drop measurement or unloading compliance method for crack growth measurement. In this paper, the results of the round robin test program including comparison of J and CTOD resistance curves will be presented and discussed.

Single Edge Precrack V-Notched Beam (SEPVNB) Fracture Toughness Testing on Silicon Nitride

2019 ◽  
Vol 962 ◽  
pp. 205-209
Author(s):  
Tjokorda Gde Tirta Nindhia ◽  
Tanja Lube
Keyword(s):  
Fracture Toughness ◽  
Silicon Nitride ◽  
Crack Size ◽  
Fracture Toughness Test ◽  
Single Edge ◽  
Razor Blade ◽  
Sintered Ceramic ◽  
Toughness Test ◽  
Toughness Testing ◽  
Diamond Paste

The previous Measurement of fracture toughness test by using bright indentation for precracked beam method (ASTM C1421) was found difficult to be carried out due to difficulty in precrack generation and measurement of the crack size. In this research single edge precrack V-notch beam (SEPVNB) is introduced as an alternative to solve the problem from previous standardized method. A real crack that can created with referred size is recognized as the best condition for fracture toughness test. The material prepared for this purpose was silicon nitride (Si3N4) produced by CeramTec (Plochingen, Germany) under the name SL200 B. It is a gas pressure sintered ceramic containing 3 wt.% Al2O3 and 3 wt.% Y2O3. The V Notch was prepared by using razor blade with diamond paste following ISO/FDIS 23146 standard preparation with more addition on precrack introduction. The precrack was introduced by so called opposite roller loading. The fracture toughness test was carried out by following procedure in ISO/FDIS 23146 . The result then was compared for validation with both single edge V-notch beam standard (ISO/FDIS 23146 ) and Surface crack in Flexure SCF (ASTM C 1421). The result of fracture toughness by using method that is introduce in this research is found 5.8270.275 MPa1/2 which is close to the result of SCF (5.335 0.222 MPa1/2). Meanwhile the value of fracture toughness by using V-notch beam is 4.9130.098 MPa1/2

Constraint Based Fracture Assessment of Seam-Welded Pipes Containing Axial Flaws

2006 ◽  
Author(s):  
Yuri Tkach ◽  
Anthony Horn ◽  
Adam Bannister ◽  
Edmund Bolton
Keyword(s):  
Fracture Toughness ◽  
Crack Depth ◽  
High Stress ◽  
Stress Triaxiality ◽  
Single Edge ◽  
Fracture Toughness Testing ◽  
Single Edge Notch ◽  
Seam Weld ◽  
Edge Notch ◽  
Toughness Testing

An Engineering Critical Assessment (ECA) of a pipeline containing an axial defect is usually conservative if standard fracture test pieces are used for the fracture toughness testing. Conventional fracture toughness testing standards employ specimens containing deep cracks in order to guarantee conditions leading to high stress triaxiality and crack-tip constraint. In the current work, single edge notch bend (SENB) and single edge notch tension (SENT) test specimens of two different a/W (crack depth/specimen width) ratios (0.15 and 0.6) were used to obtain HAZ fracture toughness of a seam weld. The influence of specimen geometry and a/W ratio on fracture toughness was investigated. The Master Curve methodology was employed to characterise HAZ fracture toughness of the seam weld in the ductile-to-brittle transition region. The reference temperature T0 was estimated using the test results obtained on specimens of different geometries and constraint levels. A series of ECAs of the pipe containing a surface axial flaw was performed and the benefits of a constraint based fracture mechanics analysis were demonstrated.

Finite Element Analyses for Thickness Effects on J-Integral Testing using Non-Standard Testing Specimens

2004 ◽  
Vol 261-263 ◽  
pp. 693-698
Author(s):  
J.S. Kim ◽  
Young Jin Kim ◽  
S.M. Cho
Keyword(s):  
Fracture Toughness ◽  
Finite Element ◽  
Three Dimensional ◽  
Specimen Thickness ◽  
J Integral ◽  
Finite Element Analyses ◽  
Single Edge ◽  
Fracture Toughness Testing ◽  
Standard Testing ◽  
Toughness Testing

This paper compiles solutions of plastic η factors for standard and non-standard fracture toughness testing specimens, via detailed three-dimensional (3-D) finite element (FE) analyses. Fracture toughness testing specimens include a middle cracked tension (M(T)) specimen, SE(B), single-edge cracked bar in tension (SE(T)) and C(T) specimen. The ligament-to-thickness ratio of the specimen is systematically varied. It is found that the use of the CMOD overall provides more robust experimental estimation than that of the LLD, for all cases considered in the present work. Moreover, the estimation based on the load- CMOD record is shown to be insensitive to the specimen thickness, and thus can be used for testing a specimen with any thickness.

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