Study On Welding Deformation And Flame Straightening Of Ship Planar Section

Welding, a flexible and efficient method for connection is widely used in manufacturing of ship and naval architecture. Welding has been applied extensively in all processes of ship building, such as assembling and welding of parts, assembling of section, and block construction. Compressive plastic strain caused by uneven heat input in welding process leads to welding deformation. Welding deformation of section has adverse effect on construction accuracy and safety use. Therefore, it is crucial to study deformation law of ship section and straighten the deformation. The paper will research welding deformation and flame straightening parameters of stiffened panel, which is one of the most common sections of ship hull.Mesh size of weld and weld vicinity is3*3*3mm3according to influence of mesh size on plate flexure and element number; The research object is simplified base on its structural characteristics to reduce element number and improve computational efficiency. The three-dimensional thermal elastic-plastic finite model of structure simplified is established and the welding process is simulated with MSC.Marc. The results show that:flexure of bottom plate looks like wave; flexure occurs between two adjacent ribs; there is no flexure at the plate where stiffened panels are; flexure of intermediate position on bottom plate between two adjacent ribs is maximum. The results are consistent with the actual situation.Flame straightening parameters for wave-like deformation of ship planar section has been researched in detail. What’s more, formula for selection of gas flow base on ’straightening energy input=welding energy input’is proposed. After heating the two back sides of stiffened plate and second correction of bottom plate free edge, flexure of bottom plate has been corrected completely and the residual deformation is less than0.5mm.