Abstract
In most cases, the fracture of machines and structures is brought by the stress concentration due to the existence of a crack. Therefore, it is important to know the strength of cracked structures, the fracture mechanics was proposed by GR Irwin. On the other hand, it is desirable to experience the experiment to understand the fracture mechanics, the teaching material on fracture mechanics that used a strip of paper with a crack was proposed by the author. In this study, the effectiveness of this teaching material is confirmed in the cases of various cracked problems.
