Volume 15, Issue 6 (November 1987)
Compliance Expression for the Middle Cracked Tension Specimen: 2a/W = f(EBV/P)
A compliance equation expressing crack length as a function of normalized compliance for the middle cracked tension specimen is developed for cracks ranging from 20 to 80% of the total specimen width. Relations are given for use over various displacement gage lengths and for materials having a Poisson's ratio between 0.2 and 0.5. These equations are based on the earlier work of Efits and Liebowitz. The equation developed compares well with this previous work, particularly for short displacement gage lengths where the maximum crack length estimation sensitivity is achieved. Further, the equation matches experimental data as well as the original work, having an average difference of 5% for all crack lengths considered.