抄録
Fracture toughness tests of specimens with arbitrary-shaped cracks were carried out. The Kc-estimation based on the published standard cord for assessing defects was significantly conservative. The one based on the proposed method for assessing defects, where the reduced circular crack with an area equivalent to an arbitrary-shaped crack was introduced, was reasonable and in good agreement with the KIc-value.
Ultrasonic tests of specimens with arbitrary-shaped embedded cracks were carried out. The estimating equation of the defect radius γei was given as 2γei=W×10(V-β'/α') where W is the path length, V the relative peak echo hight, β' and α' constants. The defect radius evaluated by using the estimating equation was coincident with the actual equivalent radius of reduced circular crack in the scatter range of ±50%.
