New Method for Analyzing Small-Scale Fracture-Specimen Data in the Transition Zone

摘要

Among the problems related to the use of small specimens for measuring fracture toughness, those concerning size effects and data scatter are perennial. An attempt was made to find a suitable method for adjusting individual small specimen fracture toughness values for size effects in the transition range of temperature. The method selected was one already proposed by Irwin. Irwin's beta /sub Ic/ equation recognizes an interaction between toughness and size. If either toughness increases or size decreases, the ratio K/sub c//K/sub Ic/ will increase. This interaction magnifies the scatter inherent in plane strain K/sub Ic/ values. Although the more common application of the beta /sub Ic/ formula is the estimation of K/sub c/ values from known values of B and K/sub Ic/, the original application was the one considered here, i.e., the estimation of K/sub Ic/ from measured values of B and K/sub c/. So the new aspect of the application described here is mainly the use of small specimen test data, analyzed inelastically. (ERA citation 08:005615)