The Development Of Ship Structural Fatigue Analysis System Based On The Hot Spot Stress Method

Fatigue failure is one of the principal failure modes of ship structures.In order to ensure the maximum safety of the ship operations, the fatigue strength should be checked in which the region of ship hull structure is prone to fatigue failure. The hot spot stress method should be used for the fatigue strength evaluation of the complex structures in 《The hull structure fatigue strength assessment guide》 (2007). The refined finite elements are calculated for the hot spot stress fatigue analysis of hull structure, the process of fatigue analysis is complex and difficult, so it is necessary to develop ship structural fatigue analysis system based on the hot spot stress method.In this paper, a fatigue analysis system of hull structure is developed based on the hot spot stress method of the CCS 《the hull structure fatigue strength assessment guide》 and the Patran Command Language, to achieve the automatic deduction corrosion allowance, automatic load calculation, automatically imposed fatigue loading, the results of automatic extraction and analysis, the oval-shaped hatch corners are automatically created and refined.The hot stress calculation influences of the five factors are researched, which are the extrapolation direction, the size effect, the refined finite element size at the hot spots, the extrapolation methods, the specific location of the refinement and the oval-shaped hatch corners of the different sizes.A 33000DWT bulk cargo ship is analysed and calculated by using the fatigue analysis system. The calculation examples of ship shows that the fatigue analysis system is stable, reliable, and efficient, practical application.