SYMPOSIA PAPER Published: 01 January 1985
STP34534S

Measurement of Stable Crack Growth Including Detection of Initiation of Growth Using the DC Potential Drop and the Partial Unloading Methods

Source

The ability of the DC potential drop method and the partial unloading technique to measure crack growth and to detect initiation of crack growth has been investigated using a number of steels and aluminum alloys. It was found that within the range of parameters investigated both of these methods can be recommended for the determination of the R curve; however, since at small amounts of crack growth, the DC potential drop method gave more consistent results, it is therefore considered to be superior. The initiation values Jo of the J integral determined by fractography were compared with JIc as obtained by current practice. It was found that ductile fracture toughness JIc is poorly related to initiation or to a specific amount of crack growth. A modification of the JIc procedure is proposed.

Two contacting arrangements of the DC potential drop method were checked for initiation detection: one indicates initiation by a potential minimum (related to a J value Jmin), the other by the intersection of the R curve with the blunting line (related to a J value Jint).

Author Information

Schwalbe, K-H
GKSS Research Center, Federal Republic of Germany
Hellmann, D
GKSS Research Center, Federal Republic of Germany
Heerens, J
GKSS Research Center, Federal Republic of Germany
Knaack, J
GKSS Research Center, Federal Republic of Germany
Müller-Roos, J
GKSS Research Center, Federal Republic of Germany
Price: $25.00
Contact Sales
Related
Reprints and Permissions
Reprints and copyright permissions can be requested through the
Copyright Clearance Center
Details
Developed by Committee: E08
Pages: 338–362
DOI: 10.1520/STP34534S
ISBN-EB: 978-0-8031-4923-6
ISBN-13: 978-0-8031-0419-8