Lifting Deformation Prediction And Control Of57000DWT Bulk Carrier Hull Section

Section and super section construction method is widely used in modern ship-building, hullsection lifting is the critical process of hull erection. Raising lifting technical level has significantimplications for shortening the berth period and improving the quality of ship construction. Thisthesis predicts and controls the lifting deformation and stress of57000DWT bulk carrier’s hullsection by using the method of FEA, and optimizes the lifting plan. This thesis mainly studiesare as follows:1) Calculating the deformation and stress of hull section caused by lifting, and studying theeffects of different load and boundary conditions on FEA. The finite element model of G901hullsection is established, the number and location of lifting-lug is decided according to theperformance of gantry crane and the basic principle of lifting-lugs’ arrangement; three boundaryconditions of FEA are analysed and compared, the method of adopting inertia relief has highaccuracy attribute to releasing the DOF of lifting-lug and considering the horizontal componentof sling; the deformation and deformation rate of deckhouse bulkhead are out of the prescribedscope, the maximum stress of deckhouse casing, web beam and longitudinal girder whichconnect lifting-lug is100Mpa, it is necessary to analyse further.2) Parameterized checking the lifting-lug’s strength and analysing the local structure’sstrength. By using the nodal forces distribution of lifting-lug’s axle hole and the interfacetechnology between VB and ANSYS, achieve the function of lifting-lug’s parametric strenthcheck of different shape for various kinds of working conditions; submodeling technique is usedfor analysing the deformation and stress of lifting-lug and hull section for higher precision, theproblem of bad grid and precision of global analysis is solved, and it also provide the data fordeformation and stress controling.3) Optimize the arrangement of lifting-lug and control the deformation and stress of hullsection caused by lifting. Minimum total strain energy criterion is taken as the objective functionand the equipment characteristic of the lifting appliance is taken as constraint condition, thegoal of lifting-lugs’ arrangement optimization is realized by using the particle swarmoptimization, the PSO model can save time compared with the enumeration method and ensurethe result accuracy; dichotomy-pso model to the minimum quantity of lifting-lug is built,comprehensive optimize the number and location of lifting-lug; by comparing the result before and after optimization, the total strain energy decrease from1535J to1240J, the maximum ofstress decrease from175Mpa to157.5Mpa, the maximum of bulkhead deformation decreasefrom36mm to9mm, and the maximum of deformation rate decrease from18mm/m to3mm/m.4) The technological process of making hull sections lifting plan is compiled by using theFEA technology, this technological process provides guide and reference for lifting other similarhull sections.