新型的一步模拟法通用初始域求解方法

NEW-STYLE AND UNIVERSAL INITIAL SOLUTION ESTIMATION SCHEME IN ONE-STEP FEM

比较目前在板料成形一步模拟法中常用到的初始域计算方法的特点,针对这些方法的缺点提出采用基于能量理论的空间网格映射法与反向变形法相结合的初始域计算方法。该算法可克服垂直投影法因零投映面积而不能迭代计算的问题,并能解决几何映射法需要寻找对称线、断面线展开法无法解决局部网格畸变的问题。复杂拉延件的实例中,通过对各种结合方案的比较得知:尽管它们获得的最终初始域是一致的,但Desbrun二次能量法及一致参数化法与反向变形法相结合的方案具有较高的稳定性和较好的计算效率,并能解决无法获取通用并高效的一步模拟法初始域求解问题。

Characters of currently used initial solution methods in sheet stamping are compared. A 3D mesh mapping algorithm based on energy theories is integrated with inverse deformation method to overcome the difficulty of iteration computation confronted by vertical projection method when zero projection area occurs; The difficulty for searching symmetry curve confronted by the geometric mapping method; The difficulty to solve mesh distortion condition confronted by section curve expanding method. Comparisons of different scheme combinations in a complex deep drawing example show that even though the finial initial solution agrees with each other, Desbrun quadratic energy method and accordant parameterization method combined with inverse deformation method is verified to be more universal, robust and efficient. This combinative method can solve the initial solution estimation with effective and universal one-stp FEM.