Commentary on Present Practice

Abstract
Emphasis on specimen size requirements and attempts to correlate KIc with simpler mechanical test results because these are areas of considerable controversy among those engaged in plane strain fracture toughness testing are presented. Problem areas in connection with plane strain fracture toughness testing indicate that the Tentative Method of Test for Plane Strain Fracture Toughness of Metallic Materials (E 399-70 T) may need revision before being advanced to a Standard and that additional experimental data are needed in order to make a judgment concerning the need for revision.