Numerical Simulation of 6005A Aluminum Alloy Friction Stir Welding Based on CEL Method
The work aims to study the distribution law of temperature field and post-weld residual stress in the whole proc-ess of 6005A aluminum alloy stir friction welding.Based on the coupled Euler-Lagrange(CEL)method,Johnson-Cook eigen-structure model and mass scaling technology was used to establish a thermal coupling simulation model to simulate and analyze the temperature field changes and post-weld stress distribution in different stages of 6005A aluminum alloy stir friction welding.The numerical model was validated by an infrared thermography temperature field test,an X-ray stress field test and a macro morphology test.During the downward pressure and preheating dwell stage,the temperature rose rapidly to 545 ℃ and was symmetrically distributed.The highest temperature in the weld area during the welding stage was 546 ℃,which occurred on the return side,and the temperature of the return side was slightly higher than that of the forward side,with an asymmetric distribu-tion.The post-weld residual stress was concentrated in the weld center on both sides of the 40 mm range.That perpendicular to the weld direction of the transverse/longitudinal residual stress distribution curve was in a"M"shape;The residual stress in the weld on both sides of the asymmetric distribution,the performance of the return side of the side was higher than the forward side,which the maximum longitudinal residual stress of-174 MPa,the maximum transverse residual stress of 206 MPa,the maxi-mum stress points all appeared in the return side.The error between the measured and simulated temperatures at the point meas-ured did not exceed 5％.The measured residual stresses at the point to be measured matched well with the simulated values,and the errors of the transverse/longitudinal residual stresses were 16.3％and 16.45％,respectively.And the simulated weld and the actual weld macroscopic morphology were in good agreement.During the process of friction stir welding,the temperature of the return side is slightly higher than that of the forward side due to the insufficient material flow,and the asymmetric distribution of post-weld residual stresses,which is slightly higher than that of the forward side due to the inhomogeneous heat distribution in the process of welding,is also presented.Through the comparative analysis of the temperature field,stress field,and macro-scopic morphology between the experimental and simulated ones,the experimental and simulated errors are relatively small,and the numerical model can reflect the real welding process,thus verifying the good agreement of the 6005A aluminum alloy weld with the actual weld.Thus,the correctness of the numerical model of 6005A aluminum alloy CEL is verified.
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