Numerical Simulation And Experiment On Hydroforming Of Cone-box Shaped Part With Differently Slope Side Walls

As a kind of soft-tool forming technology and new stamping process, hydroforming has such advantages over traditional process as simple equipment, low cost and high accuracy, especially for forming workpieces with complex-shape in one operation.Cone-box shaped parts with slant walls are more difficult to be formed than other sheet metal parts because of their wrinkling tendency of unconfined side walls and inequality of circumstantial deforming for box parts. It is more difficult for cone-box shaped parts with side walls of different slopes. Considering the difficulty of traditional process in drawing muti-slope cone-box shaped parts in one operation, hydroforming process is adopted and the combination of numerical simulation and experimental research are carried out.The FEM analysis software ANSYS is used to numerically simulate the mechanical processes of conventional drawing as well as hydroforming for cone-box shaped parts with side walls of different slopes. The results show that hydroforming process improves form ability on side walls and at corners comparing to the conventional drawing process.Through numerical simulation, stress and strain distribution during hydroforming is analyzed and places where wrinkling and rupture may occur are predicted. Furthermore, the reasons for wrinkling at corners are investigated. Numerical simulation is also applied for hydorfoming of cone-box shaped parts with side walls of different slopes , with draw beads and without draw beads respectively. The results indicated that appropriate draw beads reasonably distributing the flow resistance on area of flange, which contributes to eliminate the wrinkling possibility at corners. The key parameters effecting hydroforming, chamber pressure and blank holdeing force, are calculated. The feasible zones of chamber stress and blank holding force that benefit forming of cone-box shaped parts are obtained.An experiment system for hydroforming is designed and used for determingthe chamber pressure curves and its limits, as well as the feasible zone of blank holding force. An method of simulating real draw beads using sheet segments is presented and their suitable positions and dimensions are obtained.The coincidence of results from experimental and simulation calculation verifies the reliability of the simulation.