Work Item
ASTM WK88681
Revision of E1820-23b Standard Test Method for Measurement of Fracture Toughness
Rationale
An alternative method for measuring initial and final crack sizes from the fracture surfaces of fatigue and fracture specimens is the Area Average Method, which measures the surface area enclosed by the crack front, the specimen lateral surfaces (or the side-groove roots for side-grooved specimens), and a reference line corresponding to the origin of crack size measurements. This area is divided by the specimen thickness (or net thickness) to obtain the crack size. It is herein proposed to add the Area Average Method to E1820 as an alternative to (not as a replacement of) the existing 9 Point Average Method.
This item has already been balloted three times at subcommittee level, receiving several persuasive negatives and comments. The item has also been discussed during the two most recent E08.07.05 meetings (Denver, May 2023 and Washington DC, November 2023), as well as in several email exchanges between task group members.
With respect to the latest balloted version, this item has been significantly simplified, by removing several requirements concerning the quality and reliability of crack size measurements obtained from digital pictures of the fracture surface. It is now the responsibility of the user to guarantee that crack size measurements from digital pictures are accurate, and a list of potential issues that need to be accounted for is provided in a note.
All changes with respect to the current version of E1820 are marked with “Track Changes”.
Work Item Status
Date Initiated: 11-21-2023
Technical Contact: Enrico Lucon
Item: 000
Ballot:
Status: