Research On Shape Distortion In Curve Flanging Forming Process With TA2M Titanium Alloy Sheets

Unilateral tensile test has been conducted with TA2M titanium alloy sheets. Based on the main performance parameters measured by tensile test, the curve flanging forming and springback processes with TA2M titanium alloy sheets of 1.0mm and 2.0mm thickness were simulated using PAM-STAMP FEM software. The shape distortion phenomena after curve flanging forming process were described. A series of forming tests were performed with TA2M titanium alloy sheets in room temperature. The unfolded blank size of curve flanging ideal model was inverse solved with PAM-STAMP software to explore ways of solving the shape distortion problem.Several conclusions could be drawn as follows:(1) Four kinds of shape distortion phenomena are revealed after the FEM simulation of unloading and springback processes: the thickness distribution is unhomogeneous, the flanging height is no longer flush, the tip of out-flanging line become raised, erect sides and web is non-vertical.(2) The results of curve flanging test in room temperature validate that four kinds of shape distortion phenomena really exist, the maximal difference between two methods is 14.7%. Rasonable agreement was obtained between the predicted and measured profiles of formed parts. .(3) From the finite element analysis and forming tests, it is shown that the blank size has great influence on geometrical precision of formed part. The shape distortion are different with the difference of blank size.(4) There are two key factors which cause the shape distortion during the curve flanging of TA2M titanium alloy sheets in room temperature, the first is the unhomogeneous stress and strain distribution in forming process, the second is inexact blank size.(5) The unfolded blank size of curve flanging ideal model was inverse solved using PAM-STAMP FEM software. The results of forming simulation with unfolded blank show that: the inverse solver method could accurately calculate unfolded blank size. The shape distortion on flanging height was reduced. Verticality between erect sides and web become better.