Research On Welding Deformation Of Thin-plate Structure For High-Speed Ship Building

High—Speed Ship is a kind of vessel designed based on fluid dynamics principles and has high speed in navigation, which is widely used in passenger transport, sea monitoring, prevention of smuggling, military ships and other areas, because of the high—speed requirements, most of its hull blocks use the thin-plate structure.In construction of hull structure, welding deformation has always been a key problem which makes trouble to construction quality and production efficiency. The deformation in welding process not only affects the appearance of the structure, but also reduces the local strength and stability of construction. For thin-plate hull structure, welding deformation is more difficult to predict. Therefore, the research on welding deformation of thin-plate structure has great significance. Once welding deformation occurs, the correction will cost much labor power and material resources. Therefore, how to control and eliminate the welding deformation should be one of the key skills for enhancing welding construction quality, improving labor intensity and reducing costs.In order to reduce welding deformation, on one hand, the process of baiting, molding, assembly and welding parameters should be strictly controlled; on the other hand, anti-deformation methods and clamping fixture can be adopted to control welding deformation. All these should be set up at the basis of correctly grasping the rules of welding deformation.Welding is a complex process involving arc physics, heat transfer, metallurgy and mechanics. Welding phenomena includes electromagnetic in welding, heat transfer processes, melting and solidification, the phase—change in cooling, welding stress and deformation, etc. These factors should be controlled so as to get a high—quality welding structure. Once all kinds of welding phenomenon can be simulated by computer, we can use the computer system to determine the best design, the optimum process method and welding parameters for welding various structures and materials, as well as forecast the related deformation, which will provide basis for anti-deformation measures.This thesis firstly introduces the research background and significance of welding deformation of thin-plate structure in High—Speed Ship building, reviews the research status of this problem both in China and abroad. Then introduces the basic concepts and calculating principles for the coupled problem of temperature field and thermal stress, and detailed depicts the procedure and key points of calculating welding deformation of thin-plate structure by adopting finite element method, as well as the application of finite element software ANSYS. At last, the thesis selects a block of a in-building high-speed ship in a shipyard as model, simulates and calculates its welding deformation, then gives prediction of welding deformation in the building process.