Influence of the neutral axis displacement on the residual strength of a damaged tanker double-bottom structure

The paper presents a method to estimate the displacement of the neutral axis during the loading of a damaged ship hull subjected to bending moment. The method uses the load–end shortening relationship obtained from numerical residual strength calculations of the double-bottom structure with a fixed location of the neutral axis and establishes the force equilibrium over the whole transverse section of the ship. The set of the estimated locations of the neutral axes allows defining the new load condition to induce the bending moment on the double bottom at a higher strain rate. The new residual strength is compared with previous numerical calculations of the intact and damaged double bottom in which the bending moment is induced considering that the neutral axis is fixed during the entire simulation. The comparison shows a small reduction in the capacity of the double-bottom structure when the bending moment is caused by the new load condition.

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