Effect of Sheet Thickness on the Fracture -Resistance Parameter Kc for Steels.

摘要

Definition of fracture resistance for thin-sheet material in terms of the linear-elastic fracture mechanics (LEFM) plane-stress parameter K continues to reveal aspects of its geometrical dependency. The effect of sheet thickness on the K value of three structural steels representing four yield stress levels has been determined over available thickness ranges of 1/32to 1/4in. Within this range,less thickness dependence has been observed than was anticipated. The facts that both economy and convenience would be served if fracture resistance for all sheet thicknesses could be estimated from a limited number of specimens have given impetus to several models purporting to explain this dependency in terms of the relative contributions of a surface phenomenon,flat fracture,and a volume-sensitive mechanism,shear-lip development. Attempts to fit present data to one of the models disclose inadequacies for which there are no apparent immediate solutions. (Author)