Rationale

During the May 2024 task group meeting, common practices to add bolt holes or slots to accommodate an anti-buckling guide (particularly for wide width specimens, for example W = 30 in.) and the need to update the Notch Envelope in E561 Fig. 7 M(T) was discussed. The group was in favor of adding requirements such as those detailed in E647 Fig. 2 (particularly the bottom image with a hole and slot indicating r, and length of crack tip as a function of r), however there needs to be further investigation to ensure the crack tip stress state is not influenced by the addition of such holes and what restrictions on length/radius requirements ensure this. Prior work, around the notch envelope, in other E08.07 standards (for example, E1820, E1921 and E2472) should be reviewed. There could also be additional guidance in E561 in terms of where bolt holes can be added for anti-buckling guides.