Numerical Simulation Of Temperature Field And Stress Field And Forming Path Strategy Evaluation In Wire Arc Additive Manufacturing

As a kind of metal additive manufacturing technology,Wire Arc Additive Manufacturing(WAAM)has a lot of advantages,like high-efficient,low-cost,and highdensity.However,because of the complex thermal cycle,large residual stress will be generated during the forming process,even leading to deformation and cracking,thus seriously reducing the quality of the sample.This paper researches on the rules of temperature field and stress field in WAAM based on the finite element numerical simulation and experimental method.At the same time,the optimization of the forming path during the deposition process is carried out among the heat diffusion,residual stress distribution and warping deformation.These researches provide the theoretical basis for rules of temperature field and stress field in WAAM,and also provide the reference for path selection during the deposition process.Firstly,the temperature field model of single-layer single-bead and multi-layer single-bead is established based on the APDL in ANSYS,and the temperature field model is verified by the type-K thermocouple.Based on the experiments,the conclusions are reached: during the multi-layer single-bead deposition process,the latter layer has a re-melting effect on the former layer.With the increase of the layers,the condition of heat diffusion is worse,and the liquid melt of the latter layer covers the adjacent layer.At this time,the shape of the weld is more difficult to control,even cause local collapse,so with the increase of the layers,the waiting time between adjacent layers need to be increased.Secondly,the stress field model is established based on the temperature field model,and the experiments based on the blind-hole method are carried out.Based on the experiments,the conclusions are reached: during the multi-layer single-bead deposition process,the latter layers has an effect of stress release on the former layer.With the increase of the layers,the equivalent stress decreases gradually.During the cooling process,the deposited metal has more tensile stress because of the contraction resistance,and the final residual stress of sample comes from the tensile stress during cooling process.Finally,during the single-layer mutil-bead deposition process,the latter bead also has a re-melting effect on the former bead,by compare the thermal cycling curve in mutil-layer single-bead deposition,The conclusions are reached: heat conduction is the main transfer during the WAAM deposition process.Meanwhile,based on the heat diffusion,residual stress distribution and warping deformation,four common deposition paths are analyzed.