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拉伸成形结束后,由于残余应力的存在导致蒙皮零件产生较大的回弹,会严重影响蒙皮的使用质量。基于回弹产生的原因,从工件的应力-应变机制阐述了振动减小残余应力的机理,提出了一种振动辅助飞机蒙皮拉伸成形的新工艺方法,给出了该工艺的主要参数——频率、振幅在应用选择上的依据条件及实际运用中可选择的合理范围。以飞机前缘蒙皮拉伸成形为例,通过数值仿真模拟,分析了施加振动对成形蒙皮零件回弹的影响以及频率、振幅对改善回弹的影响,并通过实验加以验证。结果表明,在飞机蒙皮拉伸成形过程中,施加振动可以更加有效地减小零件的回弹,当选取的工艺参数频率为30 Hz左右、振幅在1.5 mm左右时回弹值最小,效果最佳。
After the stretch forming is finished, the skin part will rebound greatly due to the residual stress, which will seriously affect the quality of the skin. Based on the reason of springback, the mechanism of vibration reduction residual stress is explained from the stress-strain mechanism of the workpiece. A new process method of vibration-assisted aircraft skin stretch forming is presented. The main parameters of this process are given - - The choice of frequency and amplitude based on the conditions and practical use of a reasonable range of options. Taking the aircraft skin stretch forming as an example, the influence of the applied vibration on the springback of the formed skin parts and the influence of the frequency and amplitude on the springback are analyzed by numerical simulation and verified by experiments. The results show that the application of vibration can reduce the rebound of parts more effectively when the aircraft skin stretch forming process. When the frequency of process parameters is about 30 Hz and the amplitude is about 1.5 mm, the rebound value is the least good.