Welding Residual Stresses Analysis And Simulation&Welding Process Optimization Of Excavator’s Boom

For the bad working conditions of hydraulic excavator, working mechanism as themain component suffered force loading, the structural durability performance ofwhich plays an important role in overall performance, operational reliability, lifetimeand safety of hydraulic excavator. In our country,the industry of hydraulic excavatorstarts late, low performance and poor design,basicly depends on the copy of othercountry’s design and manufacture.It often occours that the excavator boom and stickcrack and fail during actural work,even leads to death accident.For thisreason,improving the durability of working mechanism is fatal for our excavatorindustry.Combine with the enterprise research project and actural consumption,thispaper has a deeply research on hydraulic excavator working mechanism sutrctureperformance, reliability, welding procedure and the lifetime of boom.The paper specific concerntrates on the working stresses analysis of the20tonshydraulic excavator working mechanism from XCMG during working.It is alsoincluding the residual stresses analysis during the welding process and how todecrease the residual stresses. By using finite element analysis combining withexperiment test,we analysis the stresses distribution in five typical workingcondition;on the other hand, we do a lot of work on the welding Residual stressesaccording to the actural welding procedure.The best welding succession has be chosenaccording to the simulation and experiment test data.This thesis does some research on working mechanism strength and durability byusing finite element analysis, actural test and experiment, including: 1. Building a type of hydraulic excavator’s boom3D models，simulate the heatssource model by specific software and prove its reliability by actual measurement.2. This part verifies the heat source model of welding process by simulating weldingthe simple steel plate;then proves that the materials using by the boom is so durablethat the boom wouldn’t be broken for the materials’s reason.3. By simulating the welding process, we get up to20critical weld seam residualstress distribution results and find the best, the lowest residual stresses programme；then analyze the reseasons.