Large Deck-Opening Limit Scale Research On River-to-Sea Cargo Ship

Our country has massive land and numerous rivers such as the Yangtze river,Heilongjiang etc.These rivers take the mainland and overseas connection into an importanttransportation way.The river-to-sea cargo provides a convenience and fast way fortransportation among rivers, coastals and oceans.River-to-sea direct way reduces the freightof the intermediate links, improves operational efficiency, reduces the loss of goods, befavored by lots of ship owners.Due to the dominant position of economy in the freight,therequirements for cargo ship have become to more convenience durning loading andunloading goods and stronger adaptability for different situations etc.With the Marineshipping increasingly prosperous, large scale and rapid cargo handling has been animportant problem.Under such a background,cargo ship needs appropriateimprovements,such as increasing large deck-openings,cancellation transversebulkhead,etc.Ship structure strength will be affected by above improvements.The main content of this paper include：In order to discuss the feasibility ofoptimization scheme, looking for the optimal relationship between economy and structuresafety, this paper chooses three river-to-sea cargo ships:2400t,3000t,5000t as the researchobject, puts the following optimization schemes. After that, this paper uses the applicationof MSC.Patran/Nastran to establish the finite element model of the whole ship above theoriginal type and improved type.This paper chooses full-load clearance, ballast clearanceand empty-load clearance for different working conditions, choose the highest wave inrecent fifty years for wave conditions. According to the requirements by related standardsof China classification society, basing on the direct calculation method of finite element ofthe whole ship, this paper has analyzed and checked the longitudinal strength, torsionalstrength and local strength. The checking result shows that structure strength of the originalform can completely meet the standard requirements, at the same time, with big margin.The improved form can partly meet the strength requirement. Along with the changing oflarge deck-openings, stress of the whole ship changes accordingly. This paper finallyfounds the largest size of deck-openings, which can meet the requirements of strength.