变形速率对5m瓜瓣拉形成形的影响

Influence of forming rate on stretch forming for 5m melon petal

利用有限元分析方法对5种不同变形速率对5 m球形瓜瓣拉形成形过程的影响进行了分析,预测了零件应力及壁厚分布与变形速率之间的关系。通过试验验证,得到真实拉形条件下变形速率对5 m瓜瓣的成形精度、力学性能等方面的影响。结果表明,变形速率提高对产品的表面质量及型面精度无明显影响。变形速率小于0.3~0.4 mm·s^(-1)时,随着变形速率的提高,产品的力学性能出现波动,下降趋势不明显。变形速率大于0.3~0.4 mm·s^(-1)时,随着变形速率的提高,产品的力学性能明显下降,拉形钳口处出现断裂征兆。为了提高生产效率,可采用平台范围内的变形速率。

The influences of five different forming rates on stretch forming process for 5 m melon petal were analyzed by finite element analysis method,and the relationship between stress and wall thickness distribution of part and forming rate was predicted.Then,through the experimental verification,the influences of forming rate on forming accuracy,mechanical performances and so on for 5 m melon petal were obtained under the condition of real stretch forming.The results show that the increasing of forming rate has no obvious effect on surface quality and profile accuracy of product.When the forming rate is less than 0.3-0.4 mm·s^(-1),the mechanical performances of the product fluctuate with the increasing of forming rate,and the downward trend is not obvious.However,when the forming rate is greater than 0.3-0.4 mm·s^(-1),the mechanical performances of the product decrease significantly with the increasing of forming rate,and there are signs of fracture at the clamp of melon petal.In order to improve the production efficiency,the forming rate within the platform range can be a dopted.