Direct Strength Analysis Method Of Very Large Ore Carrier Foremost Cargo Hold

The structural strength of ships,especially large ships,is an important indicator of their safety.Although the research and development of VLOC have been progressing rapidly in recent years,the research on structural strength analysis of cargo hold is still lacking.As a kind of special-purpose vessel,the arrangement and structure of large-sized ore carriers are different from that of general bulk carriers.Therefore,it is of great value to develop and perfect a set of structural strength analysis methods suitable for very large ore carriers.This thesis firstly analyzes the ship-type and structure characteristics of VLOC,and summarizes the current research status of CSR-H,structural strength analysis of cargo hold and structural strength analysis of VLOC.Afterwards,by reviewing the history of the direct calculation of the cargo hold structural strength,this thesis compares the advantages and disadvantages of two different models and evaluation methods,and analyzes the rationality and advancement of the three cargo hold model theoretically.Based on the CSR-H,a complete set of direct calculation method for the structural strength of foremost cargo hold for VLOC is established,including the modeling of the finite element model of the cargo hold,the calculation and application of local loads,the hull girder loads caused by local loads and hull girder loads adjustment.Using the direct calculation method of CSR-H,this thesis evaluates the structural strength of foremost cargo hold of three 20~400,000 DWT VLOCs,and analyzes the reason of deformation distortion of hull girder under some working conditions.The applicability of direct calculation method of CSR-H is also evaluated.Based on the theoretical analysis and the numerical calculation results,this thesis proposes two improved methods of structural strength analysis for foremost cargo hold of VLOC: the truncation method and the extension method.Through the mechanics theory analysis and comparison with the whole ship data,the validity and rationality of the two improved methods are verified.The proposed method for structural strength analysis of foremost cargo hold and related research work will provide reference for the design and safety assessment of the foremost cargo hold of VLOC.