航空结构件加工变形仿真关键技术

对航空结构件铣削加工变形仿真的关键技术进行了深入研究.编制残余应力施加通用程序,建立包含有初始残余应力的加工变形有限元预测模型;由于铣削加工,毛坯体变为薄壁工件,在进行有限元仿真过程中,提出体-壳单元与实体单元的混合单元建模方法,以提高计算效率及便于后续研究;针对工件与工作台单面约束的接触作用及其它工程中的类似单面约束问题,提出将工件视为弹性体,工作台视为刚性体,转化为接触方式进行纯压缩边界条件的模拟,对某典型工件进行了有限元仿真并与模态试验结果对比,验证了其有效性和准确性;基于生死单元技术进行材料去除模拟.通过上述关键技术的理论研究及应用,实现了航空结构件加工变形过程的有限元仿真. 

Key techniques in simulation of machining distortion for aeronautical monolithic component

Key techniques in the process of simulating machining distortion in milling due to residual stresses were researched.The calculation program was developed to generate residual stresses file and the finite element model containing original residual stresses was established.The thin-walled structure was obtained after milling machining.In order to improve simulation accuracy,a new method was carried out to model the finite element model by combining solid-shell element with solid element.Considering the contact action by unilateral constraint between workpiece and baseplate when the workpiece was located by press clamps,contact method was put forward to simulate the effect of the compression only supported by thinking of workpiece as elastic body while workbase as rigid body.The modal analysis results of representative component based on finite element simulation were compared with experiment results.The validity and reliability were verified.The material removal was realized using element birth-death.The finite element simulation of machining distortion for aerospace structures was realized by using these techniques.