In this paper, a 3-dimensional ship structural model which includes the longitudinals and stiffeners is constructed. This model can be constructed from the well-defined data structure which represents the ship structural members and their relationship. So the object-oriented concept for the data structure is introduced. The structural analysis model is automatically generated by extracting the necessary information for structural analysis from the ship structural model : Users need to handle the ship structural model only when any design change occurs because the structural analysis model is automatically generated.

A fatigue life prediction program for multiple planar surface cracks in finite plates and T-fillet joints, based on linear elastic fracture mechanics was developed. This prediction technique include the crack coalescence, mutual interation and the stress intensity concentration effect in welded joints. Total of 44 cases were compared with lida's and Vosikovsky's experimental results and it was found that the present method was a reasonable tool for the predictioin of fatigue life.

The dynamic ice forces on a structure with vertical wall and the corresponding responses of the structure are predicted. The structure was simplified as a 1-degree-of freedom system which consists of spring-mass-damper. Ice was divided into two parts : near filed and far field. In the near field, ice sheet moves with constant speed. The results obtained from the numerical simulation using the model and the experiment of indentation with stiff and flexible structures are compared. The comparisons show that the model can predict the behavior of structure and ice load with accuracy.

A numerical procedure is described for predicting steady drift forces on very large offshore structures supported by a large number of the floating bodies of arbitrary shape dimensional source distributing method, the wave interaction theory, the far-field method of using momentum theory and the finite element method for structurally treating the space frame elements. Numerical results are compared with the experimental or numerical ones, which are obtained in the literature, of steady drift forces on a offshore structure supported by the 33(3 by 11) floating composite vertical cylinders in waves. The results of comparison confirmed the validity of the proposed approach.