Abstract:
Crack propagation experiments were conducted on IS 1020 steel for various overload ratios (1·2, 1·3 and 1·4). On the basis of these experiments one power law is developed to predict the crack propagation delay period. The delay period after application of a single overload was found to increase as the magnitude of the overload increased. Crack growth also decreased after the application of an overload cycle but after a certain number of cycles it tended to return to the crack propagation rate for constant amplitude loading (CAL).