Welding Simulation Of Large-scale Hull Strucutre Using Thermal Elastic-plastic Fe Method

Thermal elastic-plastic FE method(short for TEP) is widely used in the welding simulation of welding joint or small structures owing to its high accuracy and good adaptation. However, it is hard to realize the welding simulation of large scale structures using the method for its high computational costs. This thesis brings forward the shell elements model and segmented moving heat source used in TEP method for the purpose of enhancing computation efficiency of the approach. Also, welding simulation of a large scale stiffened structure of hull is realized by the improved TEP method and the accuracy is verified through comparing the calculation results and practical measured values of the structure. The main work in the thesis can be summarized as follow:(1) By means of shell elements with section integration in ABAQUS code, a shell/solid model strategy is brought forward to improve the calculation efficiency of TEP method. A typical tee joint model is selected as an example to verify the precision of the new FE strategy.(2) A segmented moving heat source is developed and employed in TEP method to replace the transient moving heat source. One welding line is divided into several segments. The materials of welding line in one segment experience thermal cycles simultaneously and segments are heated and cool down along the direction of heat source movement successively.(3) Welding simulation of a large-scale stiffened structure of hull is carried out using the proposed method. Welding induced distortion and stress are studied based on the simulation results. The comparisons between calculated results and practical measured values verify the efficiency and accuracy of the method for welding simulation of large-scale structures.