Abstract
Fatigue tests have been carried out on out-of-plane gusset welded joint specimens under plate-bending compressive cyclic stresses and tensile cyclic stresses in order to clarify the fatigue crack initiation and propagation behavior, and fatigue strength under plate-bending compressive cyclic stresses. In the fatigue tests, the multiple repeated two-step stress tests have been also performed for the purpose of leaving beach marks in a fatigue failure surface in addition to the constant amplitude stress tests. The fatigue test results suggest that the fatigue crack stops propagating under the compressive cyclic stresses after the crack depth reaches 65 to 75% of plate thickness, propagation behavior before it come up to 50% of plate thickness under the compressive cyclic stresses are the same as those under the tensile cyclic stresses, and fatigue crack initiation life in the compressive cyclic stresses is much longer compared with that in tensile cyclic stresses.
