Evaluation of Hull Girder Stress on the Open Ship (1st report)

Abstract

As the analyzing system on the total hull girder stress on open ships such as container ships, open bulkers, etc., has been developed and structural behaviours of longitudinal members were investigated on four container ships, the outline of the system and the results of calculations are reported in this paper. This system consists of many programs which compute ship motions, dynamic loads, structural responses and response amplitudes in regular and irregular waves. The following knowledge about the stress on the upper deck in the irregular waves was obtained. (1) Maximum total hull girder stress which is composed of vertical bending stress, horizontal bending stress and warping stress, occurs at the midship or in front of the engine room. (2) At the midship, the total stress is slightly larger than the vertical bending stress. (3) In front of the engine room, the total stress is comparatively larger than the component stresses of that section, and is nearly the same level as the total stress at the midship. The further discussion concerning these results, will be presented together with the simple method to evaluate the total hull girder stress on the open ship, in the next paper.