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Optimization of loading path in incremental sheet metal forming

板材渐进成形加载路径的优化

基本信息

批准号：
02302077
负责人：
KATO Kazunori
金额：
$ 1.79万
依托单位：
Tokyo Institute of Technology
依托单位国家：
日本
项目类别：
Grant-in-Aid for Co-operative Research (A)
财政年份：
1990
资助国家：
日本
起止时间：
1990 至 1991
项目状态：
已结题

项目摘要

For the small batch manufacture of non-symmetrical shallow shells, a flexible and incremental sheet metal bulging machine has been developed using a path-controlled spherical roller.The main results of this investigation are as follows.(1) The developed sheet metal bulging machine has the following performances.Stroke : x = 200 mm, y = 300 mm, z = 100 mmTraveling speed : 30 mm/secLocating accuracy : x, y direction <plus-minus>0.03 mm (under load 0.5 kN) z direction <plus-minus>0.03 mm (under load 2(2) The computer controlled bulging machine could perform a wide range of sheet metal shaping of complex shapes, for example pyramidal shells, shells of frustum of pyramid, shallow pans and embossed panels.(3) It was experimentally showed that the optimum loading path in the incremental sheet metal forming was the path which made the strain distribution in the shell uniform.(4) In order to predict the forming limit of the incremental shaping, a new incremental bulging test by a ball punch was performed with annealed aluminum sheet, and the experimental results showed that fracture occurred when the thickness strain reached a constant value.(5) An approximate calculation method of the maximum bulging height of the shell was proposed using this fracture limit and a geometrical deformation model. The predictions for the shells were reasonably in agreement with experimental values of the annealed aluminum sheet.(6) The relationships between the forming conditions of the incremental forming and the strain distribution, the forming limit and the spring-back were clarified by the numerical simulation using the finite element method.

针对小批量非对称浅壳的加工，研制了一种采用路径控制球面滚轮的柔性增量式板料胀形机。本次调查的主要结果如下：(1)所研制的板料胀形机具有以下性能：行程：x = 200mm, y = 300mm, z = 100mm行进速度：30mm /秒定位精度：x， y方向<正负>0.03 mm（负载0.5 kN） z方向<正负>0.03 mm（负载2）计算机控制的胀形机可加工锥体壳、锥体壳、浅盘、压花板等各种形状复杂的钣金件。(3)实验结果表明，使壳体内应变分布均匀的加载路径是增量成形过程中最优加载路径。(4)为了预测增量成形的成形极限，对退火铝板进行了新的球冲床增量胀形试验，实验结果表明，当厚度应变达到一定值时，铝板发生断裂。(5)利用该断裂极限和几何变形模型，提出了壳体最大胀形高度的近似计算方法。预测结果与退火铝板的实验值基本一致。(6)通过有限元数值模拟，明确了增量成形成形条件与应变分布、成形极限和回弹之间的关系。