1987 Volume 5 Issue 2 Pages 269-272
Generally, fatigue crack propagation rate is well put in order by stress intensity range ΔKeff by considering crack closure period in crack opening process. But, in weld residual stress field, it seems that crack propagation behavior can not be exactly expressed in ΔKeff. This would be caused that ΔKeff was calculated by detecting crack full opening point which was able to be well measured experimentally. On the other hand, partially crack opening phenomena, which was presumed theoretically by considering the residual stress distribution in the case of crack laying over the tension and compression stress transition region, has not reflected in ΔK calculation process by this time.
In this paper, as mentioned above consideration, calculation method of stress intensity factor in partially crack opening condition was proposed and its model was based on superpose principle of elastic stress. As a result of applying our calculation of stress intensity range ΔKact to evaluate the fatigue crack propagation rate in welded plate, it was made clear that the crack propagation behavior could be put in order well by ΔKact than by ΔKeff.
Namely, ΔKact concept would not be only modification of KΔeff, because of applying new calculation technique for partially crack opening model.