基于平面裁切的三角形乙烯-四氟乙烯气枕成形试验及数值模拟

基于平面裁切的设计方法,制作了边长为2.5m的正三角形乙烯-四氟乙烯(ETFE)气枕模型,结合自动压力控制、三维摄影测量、激光测量等技术对ETFE气枕进行充气成形试验和测量分析.ETFE气枕经历了0~2kPa的充气加压,压力为2kPa、时间为24h的黏弹性徐变,放气至0kPa、时间为24h的徐变恢复等一体化流程.得到了各状态下的气枕内压值、上膜面整体形态和下膜面矢高值,并基于膜面形态计算出应力分布.通过与充气加压过程的几何非线性有限元分析结果进行比较分析,揭示了ETFE薄膜经历弹性变形、黏弹性徐变、徐变恢复等过程时的深刻力学性能与行为.试验结果验证了基于平面裁切的成形设计方法的可行性,对ETFE气枕结构的推广和应用具有较高价值.

Experimental and Numerical Investigations of Form Development of Ethylene-Tetrafluoroethylene Cushion Based on Flat Patterning

Abstract： An equilateral triangle ethylene tetrafluoroethylene (ETFE) cushion model with a side length of 2.5 m was developed based on the design method of flat patterning. The experimental model was performed with a form developing test, which was controlled and measured combining automatic pressure control, photogrammetry and laser sensor. The whole process of form developing included an inflation from 0 kPa to 2 kPa, a viscoelastic creep under 2 kPa lased for 24 h, and a recovery under 0 kPa within 24 h. Some original parametric data, such as internal pressure values, shapes of upper layer and rises of lower layer were obtained. The stress distributions under different conditions were calculated based on the shapes. Some profound material mechanical properties and structural behaviors, such as elastic deformation, viscoelastic creep and creep recovery, were revealed via the comparisons of results between experiments and numerical simulations. These results demonstrate the applicability, which will improve the popularization and application of ETFE cushion structure.