Effect of Different Tube Diameters on Thickness Distribution and Springback Angles in NC Rotary Draw Bending of Al-Mg-Mn Alloy Tubes

摘要

Wrinkling, rupture, springback, crack can frequently appear in the process of NC rotary draw bending.The traditional solution is trial-and-error.Now the application of numerical simulation method can forecast and eliminate the defects in advance.The Al-Mg-Mn alloy tubes with the diameters of 30 mm, 50 mm, 70 mm were bent on the numerical control bending machine.Then thickness of the bent tubes were measured.A numerical model of NC rotary draw bending process was established by using PAM-STAMP software, which was used to predict the thickness distribution and springback angle of the bent tubes.By comparing the experiment measurement with the simulation results, it is found that the finite element model can accurately predict the the thickness distribution and springback angle.The largest prediction error of the outer crest lines' thickness distribution is 9.34％, the largest prediction error of the inner crest lines' thickness distribution is 8.11％, and the largest prediction error of the springback angles is 0.55°.Effect of different tube diameters on thickness distribution and springback angle has been researched by using this FE model.Under the condition that all bending radii are three times as the tube diameters,the larger the tube diameter, the larger the thinning rate and the springback angle.