Strength Analysis of Shell Structure with Stiffenersby Finite Strip Method (Second report)

Abstract

The strength analysis of stiffened shell structure in ship hull involve to clarify strength characteristics of shell itself and the effect of shapes of the objects in addition to the effect of various reinforced ways. The first report presented a method of analyzing stiffened shells with simply supported edges and of rectangular form by means of finite strip method. And it is found that fairly high accurate solutions were obtained by this method in spite of lightening the volume of calculations.Boundary conditions for stiffened panels of actual ship-hull-structure are considered as free or elastic supported besides simply supported depending on adjacent structural conditions. Moreover, the boundary shapes of curved hull panels in ship bow or stern structure are non-rectangular occasionally and the directions of fitted stiffeners are oblique to shell edges.To increase the applicability for strength analysis of ship construction, this paper presents extensions of the analytical method described in the first report by treating following items;a) various boundary conditions for applying practical cases b) curved shell panels of non-rectangular shapes c) shell with obliquely fitted stiffeners.For the item a), it is settled by using a buckling modes of beam as displacement functions and for the item b) and c), the method of linear transformations of variables has been applied.Some examples are shown for the cases of analyzing bending of shallow shells without and with stiffeners which are of various shapes and various edge conditions. The results prove that proposed method is one of effective means for analyzing the curved parts of ship construction.