0n the Strength Analysis of the Ship Has Unsymmetrical Hull Section with Large Hatch Openings

Abstract

Recently, heavy cargo ships are apt to have peculiar hull structures to speed up loading and unloading heavy cargoes. The ship dealt with in this report is one of these ships, and has a unsymmetrical hull section with extraordinary large hatch openings. Owing to the peculiar hull structures as mentioned above, the following problems are apprehended. (1) Stress distributions in each side structure due to vertical bending moment are different from one another because of a unsymmetrical hull section. (2) Warpings and warping stresses of the hull due to torsional moment become larger because of large hatch openings. In order to clarify the problems, the whole hull structural analyses using 3-dimen-sional FEM model and full-scale measurements are carried out. The main results are as follows, (1) The results of stress distribution of the hull using the beam theory have good agreements with those of the 3-D analysis. (2) The differences of stress distribution in each side structure are negligibly small provided the scantlings of each side structure has same inertia. (3) A notable shear lag phenomenon is observed in side shells under the horizontal bending moment, however not observed in bottom shells under the vertical bending moment.