| The shipbuilding industry has a strategic position in promoting the development of the national economy.The Chinese government clearly proposes to improve the development level of the shipbuilding industry,and improve the technical level of country’s shipbuilding industry,and improve the international competitiveness of shipbuilding products.In the actual shipbuilding process,the forming of the ship’s typical bidirectional curvature plate is still manual with low automation and high work intensity which has become one of the bottlenecks that restrict the production cycle and quality of the ship.The ship’s typical bidirectional curvature plates account for about 15%～18% of the hull’s outer plates.Its processing and forming methods mainly include traditional line heating forming and mechanical cold forming.The mechanical cold forming method is more efficient than the traditional line heating forming,But the parameter control and forming quality still depend on the worker’s experience.Therefore,the establishment of a computer-recognizable knowledge system is one of the key technologies to realize the automatic forming of bidirectional curved plate.In this paper,based on the experience of workers and by means of numerical simulation,saddle-shaped plate and sail-shaped plate are the research objects,and the forming scheme is formulated and the research on how to obtain the process parameters is carried out during processing.The following work is mainly carried out:(1)This paper describes the calculation methods of in-plane strain and out-plane strain,and summarizes the current methods of calculating the strain distribution of the target shape,and improves the calculation method of obtaining the strain distribution,and realizes the visualization of the strain distribution through computer programming.(2)This paper investigates a mechanical cold forming method in shipyard,and summarizes the processing flow of saddle-shaped plates and sail-shaped plates,and analyzes the strain distribution generated by each forming tool during processing.Combining the strain distribution of the target shape and the strain distribution provided by each forming tool,the whole process is understood from the perspective of the strain distribution.(3)According to the actual processing flow of the saddle-shaped plate,the parameters in the rolling process are analyzed.The elastoplastic finite element analysis technique is used to study the relationship between the deformation shape and the three factors of the downward amount of the flat wheel,the rolling width of the flat wheel,and the initial shape of the plate.At the same time,the mutual influence between the lateral deformation and the longitudinal deformation is discussed.The database between the initial lateral curvature radius,the downward amount of the flat wheel,the target lateral curvature radius,and the target longitudinal curvature radius are constructed,and the forming scheme of the saddle-shaped plate is formulated.The accuracy of the forming scheme of the saddle-shaped plate is verified by elastoplastic finite element simulation.(4)According to the actual processing flow of the sail-shaped plate,the parameters of each processing procedure are studied.The relationship between the downward amount of the flat wheel tool,the downward amount of the bending tool,the downward amount of the single-point pressing tool and the deformation shape are studied.The forming scheme of the sail-shaped plate is formulated,and the accuracy of the forming scheme of the sail-shaped plate is verified by elastoplastic finite element simulation.In this paper,the forming scheme of the ship’s typical bidirectional curvature plate is formulated by summarizing the experience in the actual processing process.By establishing the databases,the process parameters can be obtained directly according to the information of the target shape,which is conducive to the realization of automatic forming,thereby improving efficiency of the forming,and has practical engineering application value. |
