Coupled Thermo-mechanical Analysis Of Welding Process And Residual Stress Relieving

Welding is a complicated process involving electric and mechanical, welding quality is directly related to the safety performance of the structure. Due to the welding process is a highly centralized and instantaneous heat input process, welding component will inevitably produce residual stress and deformation. The value and distribution of welding residual stress can seriously affect the strength and service life of the welded structure. As a result,to clear up the post-welding residual stress distribution of the welded structure and take corresponding measures to eliminate residual stress have very important realistic meaning.With the rapid development of computer technology and numerical simulation of welding,numerical computation for welding process by finite element method has become an important means of research on welding residual stress now.Based on ABAQUS finite element software and using parametric modeling and subroutine of double-ellipsoid heat source, the article took a terminal connector of a certain type missile launch vehicle as the research object and studied the matter of thermal-mechanical coupling in welding process of the connector. The post-welding residual stress distribution of the connector was obtained by computation and heat aging methods was used to eliminate residual stress of weldments. The main contents include:(1)Numerical simulation was performed on flat plate welding processes using the test data presented in the reference. The post-welding temperature distribution of the flat plate structure was found by computation and the heat cycle curves of the nodes corresponding to designated locations in the model were extracted and compared with the actually measured data in the reference, confirming that the simulation results of welding issues obtained using ABAQUS software were correct and reliable.(2)A finite element model was constructed for connectors and the welding processes of a total of 7 weld seams in this model, including butt welding and lap welding, were simulated numerically. The computation results data were analyzed, which helped find ultimately the post-welding residual stress distribution of the entire connector.(3)The connector was relieved of post-welding residual stress by means of heat aging process. Various heat aging schemes were developed and their computation resultscompared to find the optimum heat aging temperature. Relevant conclusions may offer some guidance to actual works in future.