Volume 16, Issue 1 (January 1988)
Determination of Kc and Residual Strength Values for Sheet Materials
Obtaining values of Kc for sheets of high-toughness materials presents difficulties related to the plastic behavior of such materials. These difficulties are also encountered in the determination of the residual strength of cracked sheets.
In this paper, an attempt is made at avoiding such difficulties by means of an empirical interpretation of Kc and the assumption of some hypotheses, experimentally verified, about the behavior of centrally cracked sheets under tension.
An empirical expression for the gross-area stress at maximum load as a function of the initial crack length is obtained and, from this expression, Kc values are calculated. For this purpose, Kc is assumed to be proportional to the maximum of the product of such stress times the square root of the corresponding initial crack length, when infinitely wide sheets are considered. A procedure is established to pass from empirical values obtained with sheets of any width to the corresponding values for a sheet of infinite width.