An Analysis of Springback in Hydroforming of Sheet Metal

• Main Authors: Yueh-Ping Chou, 周岳平
• Other Authors: none
• Format: Others
• Language: zh-TW
• Published: 2003
• Online Access: http://ndltd.ncl.edu.tw/handle/32580480420088791718

碩士 === 逢甲大學 === 機械工程學所 === 91 === Hydro-forming has become one of the rather popular manufacturing technologies in recent years, its products have the advantage of being light in weight and high in rigidity. Moreover, as a result of reducing the amount of semi-finished product and preventing from post-machining, it can cut down production capital and lower production cycling time. Therefore, it was gradually employed into the production lines of automotive, pipe-accessory and aerospace industries to replace traditional manufacturing processes such as stamping, welding or casting. Assuming a rigid die, this study employs the commercial Finite Element Software-ABAQUS for the simulation and analysis of the spring-back in aluminum alloy sheet hydro-forming, several results are summarized as follows ： 1.The spring-back angle of aluminum alloy sheet after unloading will decreases with both the increase in its thickness and the decrease in bending radius. The spring-back radius will also decreases with both the increase in its thickness and the decrease in bending radius. 2.Due to its relatively higher yield stress and smaller Young’s modulus, the spring-back angle and the spring-back radius of Al 2024-T3 sheet becomes the largest among the three aluminum alloy sheets. 3.The computed spring-back angle and spring-back radius for AL 7075-O sheet blank by ABAQUS/Standard without PU pad were not obviously influenced by both the forming pressure and blank flange length. 4.For AL 7075-O sheet blank, the computed spring-back angle by ABAQUS/Explicit with PU pad was closer to the experimental value(3.2 degree) under both the forming pressure 7000 Psi and 8000 Psi, than all the other cases. This does indicate there exists a local optimal pressure for the selected PU thickness(0.24 inch). On the other hand, under the forming pressure 7000 Psi, the springback angle for PU thickness of 0.24 inch were closer to the experimental data, than all the other cases. This tells us there exists a local optimal PU thickness for the selected forming pressure. Therefore, it is capable to reduce the error of springback angle by adequately adjusting both the forming pressure and its corresponding PU thickness.