Volume 13, Issue 1 (January 1985)
Task Group Report: Results of the Interlaboratory Test Program to Determine Percent Shear of Dynamic Tear Test Specimens
ASTM Task Group E24.03.02 on Dynamic Tear Testing evaluated the various procedures used for determining the percent shear fracture surface appearance of dynamic tear (DT) test specimens. The entire gage range of standard DT specimens was investigated. The techniques used ranged from direct visual inspection of the fracture surface to various cleavage area measurement methods using fracture surface photographs. Results based on 35 DT specimens indicated that very consistent and reproducible data can be obtained regardless of the method used. In most cases, either the original or the final specimen cross section can be used as reference, the percent shear results differing by only 5 to 10% between the two areas. Careful visual rating by a trained individual can give results very similar to the more time-consuming methods and is acceptable in most cases. Based on these results a set of recommended procedures was appended to ASTM Test Method for Dynamic Tear Energy of Metallic Materials (E 604) under the title, Determination of Percent Shear Fracture Appearance.