TY - GEN
T1 - The use of circumferentially notched tension (CNT) specimen for fracture toughness assessment of high strength steels
AU - Popovich, V. A.
AU - Opraus, Thomas
AU - Janssen, Michael
AU - Hu, B.
AU - Riemslag, A. C.
PY - 2018
Y1 - 2018
N2 - The fracture toughness of high strength steels is commonly determined by standard methods using Compact tension (CT) or Single edge notched bend (SENB) specimens. In the past the Circumferentially Notched Tension (CNT) geometry has been reported as a potential candidate for determining the fracture toughness of highly constrained cracks, theoretically approaching plane strain conditions, even for small specimen dimensions. The goal of this study is to develop a more fundamental understanding of the CNT methodology and apply it to high strength S690QT steel. An alternative prefatiguing method was developed and a straightforward relation was established between the Crack Mouth Opening Displacement (CMOD) and the Crack Tip Opening Displacement (CTOD). With the new experimental aspects, it proved feasible to determine upper-shelf CTOD values for S690QT steel, using small CNT specimens (D = 12 mm), tested at room temperature with a relative high loading rate. Furthermore, CNT low temperature values were found comparable to those of conventional SENB tests. Hence, the research demonstrates that CNT geometry allows for small scale high loading rate specimen testing, resulting in simple, rapid and cost effective fracture toughness determination.
AB - The fracture toughness of high strength steels is commonly determined by standard methods using Compact tension (CT) or Single edge notched bend (SENB) specimens. In the past the Circumferentially Notched Tension (CNT) geometry has been reported as a potential candidate for determining the fracture toughness of highly constrained cracks, theoretically approaching plane strain conditions, even for small specimen dimensions. The goal of this study is to develop a more fundamental understanding of the CNT methodology and apply it to high strength S690QT steel. An alternative prefatiguing method was developed and a straightforward relation was established between the Crack Mouth Opening Displacement (CMOD) and the Crack Tip Opening Displacement (CTOD). With the new experimental aspects, it proved feasible to determine upper-shelf CTOD values for S690QT steel, using small CNT specimens (D = 12 mm), tested at room temperature with a relative high loading rate. Furthermore, CNT low temperature values were found comparable to those of conventional SENB tests. Hence, the research demonstrates that CNT geometry allows for small scale high loading rate specimen testing, resulting in simple, rapid and cost effective fracture toughness determination.
KW - Circumferentially notched tensile test
KW - Fracture toughness
KW - High strength steel
UR - http://www.scopus.com/inward/record.url?scp=85044459589&partnerID=8YFLogxK
U2 - 10.1007/978-3-319-72526-0_47
DO - 10.1007/978-3-319-72526-0_47
M3 - Conference contribution
AN - SCOPUS:85044459589
SN - 9783319725253
T3 - Minerals, Metals and Materials Series
SP - 497
EP - 507
BT - TMS 2018 - 147th Annual Meeting and Exhibition
A2 - The Minerals, Metals & Materials Society Editor, null
PB - Springer
CY - Cham, Switzerland
T2 - 147th Annual Meeting and Exhibition of the Minerals, Metals and Materials Society, TMS 2018
Y2 - 11 March 2018 through 15 March 2018
ER -