Abstract
Low cycle fatigue tests have been made on the tee welded joints in oil storage tank and CT specimen extracted from the joint. Fatigue tests were mainly done by the method of displacement control, however some specimens were tested by load control or by control to a sloping line.
By the test, the fatigue crack propagation rate of 10-5mm/cycle up to 1mm/cycle has been obtained. Crack length in welded joint were successfully measured by ultrasonic technique.
The fatigue crack propagation rate during gross plasticity can not be predicted ΔJ critenion alone nor ΔK critenion. However, it can be done by the combination of ΔJ and Jmax criteria, giving an agreement with the extrapolation of linear elastic fatigue crack propagation rate data.
