Abstract
The objective of this study is to propose a practical method to evaluate the fracture resistance of a stably growing crack by crack energy density and to verify it through its applications to actual stable crack growth problems. The contents of this report are as follows: (1) More refined investigation of the relationship obtained before between initial crack length, present crack length, load-diplacement curves and the additional rate of crack energy density which holds until a crack starts to grow is made by using two crack models. (2) A relationship between initial crack length, present crack length, load-displacement curves and the additional rate of crack energy density caused by using the same crack models as sued in (1). (3) A method to evaluate the fracture resistance of a stably growing crack from load-displacement curves which can be easily obtained by experiments is proposed, based on the relations above.
