Rationale

A commonly used, 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. Negative votes and comments have been discussed during the two most recent E08.07.05 task group meetings (Denver, May 2023 and Washington DC, November 2023), as well as in several email exchanges between task group members. All changes with respect to the current version of E1820 are marked with “Track Changes”.