Method And Applicants Of Continuos Process Simulation On Big Hull Structure Welding

Welding is an important process in ship construction.The welding angle deformation,structural longitudinal shrinkage and bending deformation caused by welding thermal cycling,etc.are the basic problems to be considered in the precision control of hull construction.Presently,during the simulation analysis,the welding deformation is often predicted by establishing finite element model of the complete structure.However,in the actual situation of shipbuilding,the hull is a large and complex structure assembled and welded gradually by parts,components,etc.and the welding deformation of the previous process often affects the following process.So,during the welding deformation analysis,by gradually adding the component models as per the production assembly process,the evolution of the internal defects and the external deformation in the hull block fabrication can be truly and accurately analyzed,which predicts and optimizes the deformation and the design of structure,and provides the technical support for the vessel precision control.Therefore,based on the national science and technology support plan and civil-military integration project funding,the paper proposes and studies the method and application of continuous process simulation of large structure welding and assembly.First of all,via the study of hull structure and its assembling and welding characteristics and the study of finite element analysis technique,the paper explores the key technology of data transfer of continuous process simulation analysis method.To meet the requirement of data transfer and remodeling,based on the data post-processing technology,carry out the re-meshing for the finite element model of continuous process simulation to realize the transmission of deformation data.And aiming at the solution of existing problem of iterative calculation of shape function method,cell division and the proportion is proposed and designed.The conversion of the iterative calculation to a direct calculation improves the efficiency of data transmission and mapping.Secondly,to promote efficiency of continuous process simulation analysis,this paper has put forward and studied grid automatic classification technology of hull block assembling and welding based on the control unit,constructed the framework of grid division expert system,proposed inference engine algorithm,explored the rules and representing method grid division,solved the automatic dividing problem for the thick and thin grid transition,and laid the foundation for grid intelligent division system for the hull structure welding simulation.Meanwhile,considering the problem existing during the heat source model loading in continuous process simulation analysis method,this paper has designed intelligent setting system for heat source model based on rules,which has realized the automatic check of the heat source model parameters,and solved the inaccurate simulation analysis result caused by lack of operation experience and improper parameters selection.To solve the problem of long circle of simulation,large amount of work due to the large and complex structure of the ship,via the analyzation,prediction and structure simplification of the simulation work,which has improved the practicability of the simulation method,this paper has carried out the grid number budget and the mesh density change,the split of hull similar structure characteristics,the grid replication modeling and calculation of the local grid data mapping,etc.,which has laid the foundation for the effective application of continuous process simulation method for the complex and large hull welding structure,and demonstrated an example of the simulation plan for welding process of the typical hull block.Lastly,to verify the feasibility and the practicality of continuous process simulation of the hull structure assembling and welding,this paper has carried out the test and application of assembling and welding continuous process for the typical hull structure in the actual manufacture.And the problem of mesh distortion and non-convergence in the simulation analysis of multi-layer multi-channel welding is resolved by the layer model adding the layer by layer.