飞机铝合金深锥型面零件多道次充液拉深技术

Multi-step Hydrodynamic Deep Drawing of Aluminium Alloy Conical Part with Deep Cavity

目的随着新一代飞机在隐身和战斗性能方面的提高,飞机钣金零件的复杂程度和制造精度要求也越来越高。对于深型腔复杂型面零件,充液拉深是一种有效的精密制造方法。方法针对难成形、复杂型面的某型飞机铝合金深锥零件,利用理论分析、有限元模拟和工艺试验相结合的方法,设计了多道次充液拉深技术方案,并建立有限元分析模型。基于等裕量函数法和零件锥面特征,分配并优化了不同道次的材料变形量。结果对多道次充液拉深成形过程中出现的起皱和破裂的失效形式进行了研究,分析了预成形高度,液室压力和压边力等关键工艺参数对零件成形质量的影响,获得了优化的预成形高度和液室压力加载轨迹。结论结果表明,提出的多道次充液成形技术能够实现复杂型面,大拉深比的铝合金零件的整体精确成形,采用优化的工艺参数能够成形出壁厚均匀,表面质量好,锥面精度高的零件。

With the continuous enhancement in stealth and combat performances of the new generation of aircraft,the complexity of aircraft sheet metal parts and the requirement of manufacturing accuracy are accordingly increasing.Hydrodynamic deep drawing(HDD) is an effective method for the fabrication of the sheet metal parts with deep cavity and complex surface configuration.Aiming at the precision fabrication of a complicated aluminum alloy part,the multi-stage HDD technology is proposed and investigated by using theoretical analysis,finite element(FE) simulation and process experiment,and its FE models are established.Based on the equal margin function and the characteristics of the conical feature,the material deformation of the multi-stage process is allocated and optimized.In addition,the failure patterns including wrinkling and cracking during the multi-step process are discussed.The effects of key process parameters including pre-forming depth,cavity pressure and blank holder force(BHF) on the forming quality of the aircraft part are analyzed,and the optimized pre-forming depth and the loci of cavity pressure are achieved.The results mirror that the proposed multi-pass HDD technology is valid for the integral and precise forming of the aluminum alloy part with complex feature and high drawing ratio,and the deep conical part with homogenous thickness distribution,desirable surface finish and high forming precision can be fabricated by using the optimized process parameters.