Research On Technologies Of Block Lifting Sequence Optimization Based On Improved Genetic Algorithm

Since the formation of the shipbuilding industry,shipbuilding mode has been evolved from traditional riveting shipbuilding mode to modern shipbuilding mode featured by intermediate product guidance,hull block construction method and hull construction outfitting and painting integration,which shorten the shipbuilding period greatly.Guided by modern shipbuilding mode,shipbuilding process from design drawing to production management has changed significantly.Because ship monolithic building is replaced by hull block construction method,which divides the hull block properly before assembly in shipyard or on slipway.The process of ship block assembly is in the following.First,ship structure is divided properly into several sections.These sections are constructed separately with high pre-assembly degree.Then,these sections will be lifting to dock by shipyard equipment for ship block welding.After all sections are well welded together,the ship hull is fully constructed.This process is called hull erection.So far,modern shipbuilding mode is mature and applied for large-scale vessel construction at home and abroad.The intermediate product of large-scale vessel is hull section before assembly.And the time of hull section assembly takes up 40% of the ship construction period,which is a very long work time for shipbuilding of long period and complicate process.Besides,hull section assembly requires for gantry crane and available dock,which are major limited resources in shipyard.Improving the usage rate of these limited resources is vital for construction efficiency.Therefore,the realization of hull section rapid assembly is the key point for shortening shipbuilding period.Hull section assembly plan is determined before assembly process.It has great influence on utilization of assembly site and related equipment.And it determines the completion time of hull section construction plan and regional fitting plan as well.This paper studied the dock section assembly and analyzed the major factors that influence dock hull assembly rate of process after conducting research on present technological requirements and assembly scheme of dock hull section assembly.By quantified influential factors of dock hull assembly in standard process program including assembly time and lifting frequency,the dock hull assembly model is constructed.Optimization algorithm for ship section assembly scheme is presented and analytic hierarchy process method is applied for multi-objective optimization.Finally,software system for dock hull section rapid assembly scheme based on object-oriented technology is developed through technical route determination,software overall frame construction,major function modules division,design of module input and output data,determination of strategy for product safety as well as system maintenance,and design of basic object data class as well as related database.