锪窝及凹模对无头铆钉电磁铆接变形的影响

Effect of dimple structures and concave die on headless rivet deformation in electromagnetic riveting

无头铆钉具有钉杆成形均匀、连接结构的疲劳寿命高和铆钉自身密封性能好等优点,广泛应用于航空航天领域。针对无头铆钉电磁铆接过程中的成形质量控制问题,采用数值模拟与试验研究相结合的方法,运用宏观和微观分析手段,研究了锪窝结构及铆模型式对电磁铆接无头铆钉变形及干涉量的影响规律。研究结果表明:采用锪窝结构及凹型铆模能有效减小镦头45°方向剪切效应,使其变形均匀,无明显剪切带产生;相比于平头铆模,凹型铆模可有效限制材料的径向流动,更有利于提高钉杆干涉量;采用锪窝结构及凹型铆模时钉杆干涉量标准系数CV值较小,干涉量分布更加均匀。

Headless rivet is widely used in the field of aerospace industry for its advantages of rivet shaft deformation uniform,high fatigue life of structures and fine sealing performance. Therefore,the effective control of the forming quality of headless rivet was studied.Effect law of dimple structure and die form on the deformation and interference of headless rivet with electromagnetic riveting were studied from macro and micro aspects by numerical simulation and experiments combination methods. The results show that the dimple structures and concave die can effectively reduce shear effect on 45° direction of rivet upset head and the deformation of rivet is more uniform,and the shear band cannot be observed obviously in rivet head. It is favorable to improve rivet interference if concave die is adopted,because of concave die can effectively limit the radial flow of the material. The more uniform distribution and smaller CV value of interference is obtained by using the dimple structures and concave die.