Fatigue Strength Comparison Analysis Of Bulk Carriers Based On HCSR

Fatigue damage is one of the main failure modes for ship structure, which is very important for ensuring naval architecture safety and has been a vital research field for a long time in ship building. Harmonized Common Structure Rules (HCSR) makes a unification of original assessment standards of Bulk Carriers and Oil Tankers, and especially takes a large change on fatigue assessment of Bulk Carriers. Therefore, it is necessary to make comparison and analysis on Bulk Carriers fatigue strength, in order to do research on how much the standard change can influence on the structure fatigue assessment of Bulk Carriers. The thesis makes some researches on the following aspects:1. Based on the current standards, theory elements and basic method on the principle of fatigue assessment Finite Element Method (FEM) in HCSR standard are dissertated and a summary on the principle of fatigue assessment in HCSR standard is discussed, and comparison and differences in every tache between CSR-BC and HCSR have been made and analyzed.2. Researches on selection on equivalent design wave,variation on probability level and shape parameter, interpolation method of hot spot stress, etc., are done respectively. Based on calculation results, discussions on reasonableness of the changes on the above aspects between HCSR and CSR-BC are made.3. Based on a Bulk Carrier, finite element model is created and hot spots are divided according to structural alignment, calculation on its hot spot lives using FEM is conducted,and comparison between fatigue assessment results under two standards is made.4. Introduction on the simplified stress method of HCSR Bulk Carrier fatigue assessment is made, the model of typical transverse section is created and analysis on the differences between the calculation results of the Bulk Carrier typical transverse section longitudinal stiffener fatigue lives under two standards is conducted. Researches on the joint stress concentration factor are made, and when the assessed joint format is beyond the applicability of the standard, a reasonable calculation method of stress concentration factor is offered.