Volume 19, Issue 2 (March 1991)
Plastic η and γ Factors for Compact Tension Specimen in J-Integral Estimation
The empirical expressions for the plastic η and γ factors adopted by ASTM in the standard test methods for Jlc and J-R curve testing (E 813 and E 1152) were determined from the results of experimental work. This note proposes instead expressions of ηp and γp that are derived from a limit load solution. The results show that over the range of crack lengths recommended for testing in the ASTM standard test methods, a/W = 0.5 to 0.75, the proposed ηp value is 5.11 to 1.42% greater than the ASTM value, and the proposed γp value is 12.93 to 5.82% greater.