The application of finite element methods to ship structures

Abstract

A practical method of overall finite element analysis of a ship structure based on the modern theory of a beam is proposed in this paper. The analysis consists of three steps, the first of which is evaluation of various section properties of a ship cross-section, especially the torsional stiffness. The second step of analysis is solution as well as formulation of overall stiffness equation of a given ship. In the formulation of overall stiffness equation, a special consideration is made on the discontinuity of nodal points which may exist between two adjacent beam elements. The third step of this method is shear deformation analysis of a ship structure based on the finite element formulation of Semi-Inverse Method, by which not only shearing stress distribution but also the effect of shear deformation on the beam displacement and shear lag problem can be studied. The author believes that these computer programs for overall ship structural analysis will be very practical with respect to computer time and labour from the design point of view. He also believes that combined use of the present computer program at the basic design stage and the conventional general purpose computer program at the detail design stage will make ship structural analysis effective and powerful. In conjunction with this point, a brief introduction of the ‘PASSAGE’ Program will be also made, which is a conventional general purpose computer program for ship structural analysis now under development in Japan.