Study On Accuracy Control Of Hulls

Ships' accuracy control technique is an important means to ensure ships' quality and reduce the cost of production. Many advanced countries have improved in ships' accuracy management. Youming shipyard in Japan has no residual quantity in all blocks during the manufacturing. Domestic ships' accuracy control technique has been developed for many years, but most shipyards have no residual quantity only during producing blocks. Ships' accuracy control technique has been extended lowly, which has only compensated quantity instead of residual quantity during whole ships' production. And the research of compensated quantity is deficient.This paper has researched the system of ships' accuracy control technique and applies size chain principle to ships' accuracy management.The paper has managed the problems of error transfer and tolerance assign of ships' dimension by the principle. We have built the database about ships' weight and centre of gravity by the probabilistic technique of the principle. Shipyards can monitor and control ships' weight and centre of gravity during the whole production from design to complete.The paper has researched weld distortion by thermal elasto-plastic finite element techniques, and carried out an experiment. The main content is how to force elastic reversed angular distortion. This paper has simulated the welding process of the T-Joint Fillet Structures used thermal elasto-plastic finite element techniques by MSC's MSC.Marc/ MSC.Patran. The study has calculated the distortion of the structures which are different thickness and are thrown different heat flow. According to analysis of calculating result, the structures thrown elastic reversed angular distortion before welding have no angular distortion after welding. An experiment has been carried out in Dalian Shipyard that prove elastic reversed angular distortion is effective means to control weld distortion in ships' accuracy management.The research has introduced the compensation database simply and used the practice data from Dalian Shipyard to study mathematical models construction for weld shrinkage by BP neural network. This paper has built the mathematical model calculating components compensation value by welding distortion.