Prediction Of Residual Stress And Distortion Of Typical Joint Of Hull Structure Based On Shell Element

Welding is widely used in the hull manufacture industry as aneffective and reliable connection method. Due to the intense temperaturechange in the welding zone and its vinicity, residual distortion and stressare caused in the structure, and the initial imperfection will reduce theeffective section-area of hull structure and make it prone to lose its stability,thus greatly affect the ultimate strength of structure. In order to accuratelypredict the ultimate strength of hull structures and ensure its safety, it’snecessary to reasonablly acquire and consider the distribution of residualstress and distortion after welding. Thus the work of this dissertationfocuses on the following aspects:(1)The experiment of butt welding is briefly introduced as well as theprocess of the measured data. Based on Abaqus code, shell elements withsection integration are used to perform the thermal elastic-plasticnumerical simulation of butt-welded plate. The2D shell model isestablished and the mixed moving heat source comprised by uniform bodyand Gauss surface flux is adopted to describe the distribution of inputenergy. The material physical property including specific heat andconductive coefficient is temperature dependent. The result is comparedwith that of3D solid model of equal mesh size and the experimental data.(2)Mixed model of solid and shell is put forward to carry out thermalelastic-plastic analysis to study the T fillet Joint welding under freecondition, and the temperature field、residual stress and distortion result areinvestigated and compared with that of3D solid model to verify itsfeasibility and accuracy.(3)The deck girder of hull structure is studied by thermal elastic-plastic analysis based on3D shell element, and the residual stressand distortion of stiffened plate under different constraint conditions andwelding sequences are discussed as well as the stress concentration at theends of plate. This lays a good foundation for the further research of theultimate strength of stiffened plate considering the welding imperfection.