Numerical Simulation Research Of Weld Stress Field After Welding Trailing

Welding is a rapid,non-uniformed heat process．there is the great temperature gradient near welding seams．With the different of temperature distribution．inflation and shrinkage in different materials．weding seams have a complex three—dimensional residual stress state,along with produce temporary or permanent welding deformation．and would inevitably produce complex in the welding residual stress．cracks．porosity,defects,influence the quality of welding structure and performanceWelding with trailing peening is the welding new technology,which developed inrecent years,have some advantages snch as equipment simple．flexible opel'ation．high working efficiency and so on．Through trailing peening on the workpiece．it canefl?ctively reduce and elimate welding residual stress,avoid welding crack,improvefatigue strength of the welding seams．adjust welding residual stl_eSS distribntion Inthe s),stem ot'welding with trailing peening．it is a significant inflence on l-elif ol'welding residual stress to choice parameters of vibratory hammer．According tovariation of temperature field during welding process．it can@tel mine someparameters such as the shape of vibratory hammer,the time of beginning to peening．the force and frequency of peening．So it call control effect of trailing peening andelimate welding stress．Through simulated welding process with computer．we canknow the distribution of welding temperature field and stress field at difercntial time．and offer reference for the position and beginning time during welding,aith trailingpeeningThrough the discussion of the welding process system finite element analysismethod and theory．the welding process the temperature field and stress field or thebasic theory and numerical simulation analysis method was studied．and use themethod ol,thcrmal—structure couple．first simulation in the process of weldingtemperature distribution,and then put temperature field simulation results to loadform tile analysis of the stress field added to the process that call get tile distributionof stress field:Then the simulation of tile temperature field and stress field distribution rule and compared to the traditional．and througll experiment verifiedThe research works of the paper are as following:fil'stly,through reasonable assumpting of welding process．using the finitc element method and theory．it make a 3-D models of workpiece which wled multi—seams in fiat．simplify boundary,'conditions and loads．divide grid structure and confirm node and element type；fhe second,establish the gaussian flmction of the distribution of the surface heat source nlodel．make program with APDI．of ANSYS software,rcalize the nlove of heat source．use the dead—live method,slove the simulation problem of heat source inmulti—seams flat during the welding process．Thirdly,it can slove the phase transitionproblem of melting and solidification and slove the problem of the convergencedifficulty or the un—convergence with Newton—Raphson method,and then have areal-time dynatic simulation tO welding process,get the distribution graph and law oftemperature field in welding workpiece；then using the temperature result as load withcOuDle method,it can receive the distribution graph and law of stress field,comparewith the traditional theory of welding,provide the theory basis for the opportunity tobegin tO peen,and SO confirm the parameters about welding trailing peening；Lastly．itcan dO some experiments to measure the temperature field and stress field in theworkpiece during welding process,compare the measure result with simulated resultwhich received on the computer,then verify simulated result and offer more be~erparameters to peen the workpiece during welding process．It Drovides theoretical basis and guidance tO have a ansyis for 3-D temperature field and stress field in the simulation process of multi—seams welding flat,and Dromote the finite element analysis method in welding analysis and application in engineering...