某复杂蒙皮拉形中起皱缺陷的消除

Elimination of Wrinkle Defects from a Certain Complex Aircraft Skin during Stretching

目的对某复杂飞机蒙皮零件在拉形工艺过程中的起皱行为进行研究,以得到消除起皱缺陷的方法。方法分析了该蒙皮零件的型面特点,指出了拉形过程中出现起皱的原因。设计了3种改进的拉形方案,采用有限元仿真的方法对这3种方案进行模拟评估,确定了对起皱缺陷改善最为明显的一种,基于设备与工装的限制对该方案进行了调整,作为改善拉形质量的最终方案,并再次进行了有限元仿真验证。结果根据改进方案,在拉形工艺设计软件上生成拉形设备的数控代码,进行了生产性验证,与有限元仿真结果符合的很好,基本消除了起皱缺陷,提高了零件的成形质量。结论通过对拉形工艺中工装模具的优化设计,可以减少或避免起皱缺陷的出现。

Wrinkling during the stretch forming of a certain complex aircraft skin was studied to obtain the method of eliminating the wrinkle defects. The aircraft skin surface characteristics were analyzed, and the causes for the wrinkling during the stretch forming process were pointed out. Three modified stretch forming schemes were designed, and evaluated with finite element simulation. The most effective scheme was picked out based on the improvement of wrinkle defects. The scheme was then adjusted according to the stretching device and tools, resulting in the final scheme for improving the stretch forming quality, and finally another finite element simulation verification was conducted. According to the improved scheme, CN code for the stretching device was generated with the stretch forming technology design software. Production verification showed good consistence with the finite element simulation result. Wrinkle defects were basically eliminated and the forming quality of the parts was improved. The occurrence of wrinkle defects could be reduced or avoided by design optimization of the stretching tool during stretching forming.