板材三维曲面零件的坯料计算与变形逆分析

Blank Calculation of Three-dimensional Sheet Metal Parts and Inverse Analysis of Deformation

坯料计算是板材三维曲面零件成形工艺设计的重要问题之一。根据变形均匀原则及材料体积不变条件建立了一种基于三角形网格的坯料计算方法 ,该方法通过迭代格式使目标泛函极小化 ,得到零件的初始坯料。根据平面应变假定及三角形单元常应变条件 ,进行了由目标零件到坯料的变形逆分析。通过多点成形实验检验了坯料计算方法的精度与可靠性。

Blank design is one of the important problems in the forming processes of three-dimensional sheet metal. A new algorithm to calculate blanks based on triangular mesh was presented according to the conditions that the deformations in material are most evenly distributed and that the volume remains constant. By minimizing the objective function with an iterative scheme, the initial contour of blank was obtained. On the basis of the assumption of plane-strain and the constant-strain condition in triangular element, the deformations from the objective part to the initial blank were analyzed. Multi-point forming tests were carried out to check the accuracy and reliability of the method.