Cargo Hold Strength Assessment Method Research And Finite Element Analysis Of Comprehensive Replenishment Ship

Comprehensive replenishment ship is highly functional and efficient.Its large loading capacity can achieve the transportation and replenishmentof both liquid and dry cargo. It has now become an essential kind oflogistical support ships which provide a variety of supplies for ships at sea.Cargo hold structural strength is the key to ensure ship safety andoperational ability. Compared with traditional civil ships, the loadingpattern of comprehensive replenishment ship can be quite different due toits varieties of supplies. The loading pattern leads to complicated structuraldesign and difficulties in strength analysis. At present, there is no rules orguidelines for cargo hold strength calculation aiming at this ship type.In the thesis, according to the loading pattern and structuralcharacteristics of comprehensive replenishment ship, relevant rules andregulations for course mesh yield strength calculation were compared.Theoretical basis and application of specific requirements were discussed.Extent of cargo hold finite element model was determined, which differedfrom the rules. And corresponding loading conditions were designed.Relevant rules and regulations for fine mesh analysis at local highstress areas were compared and analyzed. Detailed screening criteria fordifferent structural members are considered in Common Structural Rulesfor Double Hull Oil Tankers, which are more comprehensive and specific. Requirements on mesh size and element type in fine mesh zones are alsohigher, in order to better represent the actual geometry of structural details.Relevant rules and regulations for buckling strength assessment werecompared and analyzed. Requirements on structural size of bucklingassessment model are much stricter in Common Structural Rules forDouble Hull Oil Tankers. The corresponding assessment method fullytakes the characteristics of primary structural members into consideration,leading to better structural performance. While in CCS guidelines for oiltankers, buckling performance of plates is completely limited under linearelastic assumption, which seems to be too conservative.Coarse mesh model yield strength calculation, fine mesh finiteelement analysis and buckling strength assessment of a comprehensivereplenishment ship were accomplished based on the proposed cargo holdstrength assessment method. The rationality of designed loading conditionswas verified by comparison with additional examples. And according tothe assessment results, suggestions for local structural design were putforward to improve the stress distribution and ensure the safety of hullstructure.The research results in this thesis can be helpful and provide referenceand basis for the structural design and strength assessment of similar shiptype.