反射器夹层面板精密成形原理

对高精度、大面积不可展双曲反射面的制造问题,提出了基于"离散钉模、真空负压、蜂窝夹层、应力释放、回弹补偿"的高精度反射面板成形原理;建立了四边自由面内多点约束的薄板大挠度弯曲解法及夹层板成形过程仿真模型,用于确定成形工艺参数;利用动力显式和静力隐式算法相结合的方法实现成形过程仿真;通过开缝和开槽方法释放面内压应力,确定了面板开缝和开槽方案;通过逆向修正离散模包络面,使其与成形模拟得到的夹层板型面误差最小,得到模具修正因子,补偿回弹误差.在此基础上开发了夹层板精密成形CAE系统.该方法制造的面板型面精度RMS达到25 μm以下,已成功地应用于多项大型紧缩场和毫米波天线的制造. 

Principle of precision forming for sandwich panel of large antenna reflector

To solve precision forming problem of the antenna panels with large non-developable double-curvature surface, the precision forming principle was proposed, based on "discrete nails die, vacuating press, honeycomb sandwich, stressrelease in-plane, and springback compensation". The problem of rectangle thin plate with free edges and constrained at arbitrary inner points with large deflection was discussed. An explicit/implicit hybrid FEM method was used to simulate the forming process and springback to determine the processing parameters. The slotting and notching techniques were developed for releasing the compression stresses of panel in order to ensure good fittability of panel on nails die. The compensation of springback has carried out by modifying discrete nails die, the adjusting coefficient of nail-head height was obtained by minimizing the shape-error between modified surface and simulation shape. The CAE system for precision forming of antenna panels was developed and was used successfully in several actual projects of compact antenna test range and millimeter-wave antenna. The precision of reflector panel can reach below 25 μm.