Abstract
A C-shaped specimen is suitable for testing thick-walled cylinders. Fatigue crack growth tests were conducted by using the through cracked specimens with different ratios of outside to inside radius. It was shown that the fatigue crack propagation rate, da/dN, was related uniquely to the stress intensity factor range, ΔK, by following expression,
da/dN=C(ΔK)m
This relationship is consisted with that obtained by using the compact specimens fabricated from the same orientation.
From the fatigue crack growth tests using the surface cracked specimen, it was shown that the crack depth could be measured accurately by the End-on ultrasonic method, and the aspect ratio variation chracteristics with increasing crack depth was clarified. Moreover, it was found that the fatigue crack propagation rates, da/dN and db/dN, in the specimen width and through thickness directions were related to the presumed stress intensity factor ranges, ΔKa and ΔKb, respectively.
