Efficient Prediction And Control Of Welding Deformation Of Typical Plane Segmentation

Plane segmentation is widely used in the field of ship and marine engineering,especially in the superstructure of ship hulls and offshore platforms.The main workload of ship and offshore platform construction is concentrated on welding,so the quality of the welding determines the quality of ship and offshore platform.The traditional method is to predict and control welding deformation through the experience of shipbuilders and a large number of tests.This method is time-consuming and expensive,and is not suitable for the prediction of welding deformation of large and complex sections of ships and offshore platforms.With the rapid development of computer technology and the continuous improvement of numerical calculation methods,finite element numerical simulation technology has become the mainstream means of predicting welding deformation.In this paper,based on the elastic finite element analysis of inherent deformation,the overall welding deformation of the two plane sections of the 923 section of the hull superstructure and the B514 section of the semi-submersible lifting and dismantling platform is predicted,and the measures of inverse deformation and sequence optimization are used to control the segmented welding deformation.First summarize the typical welded joints of two plane segments,and then calculate the inherent deformation of all typical welded joints.Based on these inherent deformation data,the natural deformation database is established.Through elastic finite element analysis and calculation based on inherent deformation,the welding deformation of two plane segments is calculated.Finally,the inverse deformation method and the method of optimizing the welding sequence are used to control the welding deformation.The results show:(1)Using parallel computing technology to perform thermal-elastic-plastic finite element calculation on 21 typical welded joints,the inherent deformation of the joint is obtained;compare and analyze elastic finite element calculation results with thermal-elastic-plastic finite element calculation results to verify the accuracy of intrinsic deformation;based on the inherent deformation data of the joint,an empirical formula between the heat input and each inherent deformation component is summarized,the formula saves time for subsequent calculation of the inherent deformation of typical joints and greatly improves the calculation efficiency;(2)Carry out the elastic finite element calculation to obtain the prediction results of the segmented deformation,and compare the calculated results of the segmented elastic finite element with the actual measurement results,the accuracy of predicting the out-of-plane deformation of the semi-submersible lifting and disassembling platform B514 and the outer deck sheet body welding surface is verified by the elastic finite analysis method based on inherent deformation;then the welding deformation of the 923 segment of the superstructure of the hull is predicted.The out-of-plane deformation cloud diagram in the Z direction shows that the overall deformation of the bottom plate is not large,and the large deformation is concentrated near the opening and floor boundary;(3)Comparing the calculation results of the B514 segment under the three designed welding sequences(welding sequence 2,3,4)with the calculation results under the actual welding sequence(welding sequence 1),it is found that the designed welding sequence 1 is the best solution among the four welding sequences;through calculation,it is determined that the factor affecting welding deformation is corrective assembly;(4)The anti-deformation method is used to control the welding deformation of the 923 segment of the superstructure of the hull and the B514 segment of the semi-submersible lifting and dismantling platform,that is,the out of plane deformation of two plane sections calculated by elastic finite element method based on inherent deformation,and then give an initial reverse deformation value(determined according to the previous calculation)of the wing plate of the corner joint or the base metal of the butt joint,so that the initial deformation and the welding deformation cancel after the welding is completed,thereby controlling the welding deformation;the deformed hull superstructure 923 segment and the semi-submersible lifting and dismantling platform B514 segment were subjected to elastic finite element calculation according to the actual welding sequence,and compared with the elastic calculation results without reverse deformation under the actual welding sequence.The out-of-plane deformation of the segmented overall weld after reverse deformation is greatly reduced.