翘曲修正曲面展开四节点单元在某汽车油底壳快速成形模拟中的应用

Application of Warpage Modified Four-node Element in One-step Forming Simulation of Certain Automobile Oil Box

为提高油底壳成形性有限元数值模拟计算效率，研究了国内外一步成形逆有限元法的最新研究成果，并对一步成形逆有限元法进行了改进。提出带翘曲修正的曲面展开四节点等参膜单元模型，应用于某汽车油底壳成形模拟，将模拟结果与增量法模拟结果及实验结果进行对比，表明改进后的一步成形模拟结果与增量模拟结果非常接近，计算时间仅为增量法的3％～5％，进而验证了一步成彤方法的有效性和实用性。

To further enhance efficiency in the forming simulation of automobile oil pan, one--step forming finite element inverse approach was improved. The four--node isoparametric membrane element was applied to one--step forming simulation and then element warpage was modified, which was caused by conditions that the four nodes of spacial quadrilateral element may not be coplanar. Instead of increment method, one step codes were implemented to simulate practical forming of a certain automobile oil box. By comparison of the simulation results through modified one--step forming method with that by increment method, it is found that they agree very well, while time used for computation is less than one twentieth of that of increment method, which proves the validity of the proposed method.