Abstract:
Objectives This paper studies a method for quickly and accurately estimating the total longitudinal bending stress of ship types with integral superstructures.
Methods Based on previous researches, several finite element models (FEMs) of a typical ship with an integral superstructure were constructed. The effectiveness of the superstructure was then calculated according to the three definitions and compared with a number of commonly used simplified formulas (e.g. empirical formula of Lloyd's code, Russian Formula Ⅰ, Russia Formula Ⅱ).
Results The results show that the predicted values of these simplified formulas are close to those of the FEM when the point is near the middle area of the superstructure, and quite different when far from the middle area. A comparison of the effectiveness of superstructures with various lengths, heights and thicknesses indicates that the effectiveness calculated by Russian Formula I is not much different from the third definition. In addition, the stress predicted by Russian Formula I combined with the third definition are in good agreement with the FEM results.
Conclusions The proposed method can be used as one of methods for predicting the bending stress of hull girders in ships with integral superstructures.