Study Of Welding Residual Stress On Basket Of Double Pusher Centrifuge

Welding is an extremely complicated process, it needs to study the thermalelastic-plastic problems sequenced by the factors, such as phase change plastic andnonlinear, etc.; it is time-consuming and costly to accumulate data for extra-largeweld such as basket of double pusher centrifuge. This essay studies a numericalsimulation method as a cost effective solution to the cracking of basket welding.On the basic theories of welding thermal field, various heat source models andheat elastic-plasticity, this essay studies the numerical methods of welding thermalfield to try to solve these residual problems: nonlinear parameters of material underhigh temperature, handling latent heat of phase change etc. The essay goes further toinspect heat sources by comparing simulation results of application of Gaussian heatsource model double elliptic heat model to thin plate.The essay builds a3D dynamic simulation program using APDL language tosimulate and solve the coupling of welding thermal field&structure field. By thecontrol of element birth and death, and usage of double ellipsoidal model to realizethe fast movement of welding heat source, the essay studies the prediction methods ofthe thermal field and residual stress distribution using flat butt welding as an example.The way to simplify the fusion zone is also discussed.Moreover, the essay compares simulation results with the experimental data ofwelded flat butt generated by X-ray stress analyzer to verify the accuracy of thesimulation.In next sections, a3D Finite Element Model of pusher centrifuge baskets is builtand simulates once-welding and twice-welding to analyze the thermal field,deformation and residual stress distribution of basket welding to conclude that themaximum residual stress is at the upper and lower surfaces of the welding joint, and it becomes smaller vertically towards the core. Different FEA results are compared toprove that the twice-welding can get more optimized results.In last sections, the essay experiments the method to take residual stress as initialstress, and analyzes the stress in specific applications of pusher centrifuge to evaluateand compare the computation results. Also, by Monte Carlo method, the essaysanalyses th reliability of the drum.In conclusion, this essay provides a theoretical ground and guidance to weldingthermal field and residual stress analysis of complex welding structures.