双曲度蜂窝夹层结构高精度面板真空负压成形回弹预测

Springback prediction on vacuum negative pressure forming for high precision panel of double-curvature sandwich structure with honeycomb core

针对双曲度蜂窝夹层结构面板真空负压成形的精度控制问题,建立了基于半解析、半数值模拟的回弹预测方法。首先,利用有限元方法建立了单层铝板的压贴分析有限元模型,获得了铝板大挠度弯曲时的膜应力。然后,结合薄板大挠度弯曲平衡方程求解单层铝板的临界贴模压力,并基于临界贴模压力建立了夹层结构面板真空负压成形的回弹预测有限元模型,从而实现对双曲度蜂窝夹层结构面板的回弹预测。最后,开展了夹层结构面板真空负压成形试验,有限元模拟和成形试验得到的面板型面精度偏差为9.3%,表明建立的回弹预测模型具有较高的预测精度。

For the precision control problem of vacuum negative pressure forming for double-curvature sandwich structure panel with honeycomb core,a method of springback prediction was established based on semi-analytical and semi-numeric simulation.Firstly,the finite element model of compression analysis for single-layer aluminum plate was established by the finite element method,and the membrane stress of large deflection bending for aluminum plate was obtained.Then,the critical membrane pressure of single-layer aluminum plate was solved by the large deflection bending equilibrium equation of thin plate,and the finite element model of springback prediction for vacuum negative pressure forming of sandwich structure panel was established by the critical membrane pressure,and the springback prediction of double-curvature sandwich structure panel with honeycomb core was accomplished.Finally,the vacuum negative pressure forming experiment of sandwich structure panel was carried out,and the deviation of surface accuracy for panel obtained by finite element simulation and forming experiment was 9.3%,which indicated that the established springback prediction model had higher prediction accuracy.