| Three large scale single cell box girders and two triple cell box girders of AL-6XN superaustenitic stainless steel simulating components of double hull ship structures were tested under repeated reversal bending of constant magnitude for examining fatigue behavior of such components. The flange and web plates of the boxes deflected repeatedly out-of-plane (panting). Local stress ranges along the boundaries of flange plate panels were much higher than the nominal stress ranges and fatigue cracks developed at these locations of higher stress ranges. The fatigue strength category in terms of S-N curve is, therefore, lower than that for plate panels without out-of-plane deflection.; The experimental study is supplemented with a parametric finite element study. The results of the finite element study indicate that the local maximum stress range of an edge loaded plate with initial out-of-flatness can be predicted. With this knowledge and using the ASSHTO fatigue design curves, certain parameters, such as the slenderness ratio can be limited or adjusted to control fatigue damage. |
