Study On Key Techniques Of Structural Design Based On CSR For Bulk Carriers

Common Structural Rules(CSR) for bulk carriers and oil tanks is efficient on April 1st 2006.This is the first time to unify the ship construction rule for IACS.New rules aim at satisfying with the requirement of building stronger,more durable and suitable.That will be safer and will use more steel compared with old rules,so will make the cost rising.But CSR based on new design method,steel distribution will be more reasonable.Compared with existing rules,CSR is neutral,and it is more suitable for ship industry of China.Simultaneity,CSR will promote the ship updating and the industry development,and also it will reduce the effect on original market from new market.CSR Rules' main points are:net scantling,design load,hull girder ultimate strength,direct strength analysis,fatigue,buckling etc.There are many excellent views,including the new erosion model;the advanced wave load model making calculation for load more reasonable;the ultimate strength concept increasing the transparence of ship strength;the direct strength analysis technology suitable for large scale ship structure design;fatigue assessment technology promising the 25 years life for ships.This paper expounds the safety rules development of bulk carriers;explains the background,signification and main technical points.Introducing the JBP characteristic and basic content,and comparing with the CCS rules.Then based on the existing bulk cargo ship of 35000DWT,a new ship satisfied with CSR is designed and computed with the software of CCSS JBP SDP,in order to seek the character of the new rules and the traditional rules,only the midsection and bulkhead of the ship were taken into consideration,because weight of cargo tank area is take most count of the light weight of the whole ship,finally the midship structure is checked and analysised with the method of FEM.The calculation will accomplished by FEA software MSC.Patran/Nastran.The main procedure is creating the FEA model,the yield strength calculation,the buckling strength calculation.Comparing the ship structures designed based on the CSR to CCS rules,we can conclude that if all the ship is built with common ship steel based on CSR,the light ship weight would increased by 10%at least,and about 3%for the high tension ship steel(AH32 or AH36).As a result,it is necessary for the new ship to adopt the high tesion steel for ship design based on CSR,which is a safe,scientific,reliable and feasible rules,so we should generalize and implement the new rules.