A Study On The Prediction And Control Of Structure Deformation During The Construction Of Combat Ships

During the construction of a ship,the deformation of the structure is inevitable,due to the influence of welding,docking,lifting,equipment loading,sunshine and temperature changes.In contrast with civilian ships,the structural deformation during the construction of surface combat ships not only affects the construction accuracy and quality,but also seriously affects the calibration of onboard weapon system and aviation support system.In order to improve the China’s construction ability of ships in accuracy,master the deformation pattern of structures under typical loads or working conditions,and ensure the precision calibration of onboard equipment and system,this thesis studies the deformation prediction methods and deformation control measures due welding,sectional lifting,docking of ship or sections.The main research contents of this thesis are as follows:1)Based on the thermal elastoplastic principle of sequential coupling,the finite element analysis method for welding deformation of hull structure is established.The applicability of the method for analyzing is validated by comparing the finite element results for plate butt welding deformation with experiment.On top of this,the welding deformation and angular welding deformation under different boundary conditions are calculated,and the influence of different welding boundary constraints on the welding deformation is analyzed so as to obtain the boundary constraints for deformation control.2)According to the characteristics of segmental hoisting of ship sections and the adaptability theory of hoisting points,a particle swarm optimization algorithm for determining hoisting points is adopted,and the prediction method of segmental hoisting deformation is established in combination with the finite element method.On this basis,the screening of lifting points and forecasting of hoisting deformation of the fore section,the general section of the superstructure,and the midship section of the engine room are carried out respectively,and the applicability of the method is verified.3)Based on the general principle of ship pier layout and elastic support beam theory,the docking pier layout design method is proposed,and the docking deformation prediction method is established by combining the finite element method.The docking deformation of the whole ship is analyzed,and the effectiveness of the method is verified.4)Based on the docking deformation,the structural deformation caused by temperature difference under the action of sunshine was further studied.Based on heat transfer and thermal stress analysis method,a method for analyzing the deformation of ship structure under the action of sunlight is established.Based on measured environment temperatures and deck temperatures under the action,the deformations of the engine room section,fore section and the whole ship were predicted;the deformation patterns of structures are analyzed,and the "lotus leaf deformation" phenomenon is verified.