ETFE气枕结构成形设计方法与试验

为研究ETFE气枕结构的成形方式，引入基于找形分析的零应力态三维裁切和基于材料非线性的平面裁切两种设计方法，对比了两种方法的设计过程，并分别分析了两种方法的设计分析过程和力学模型.通过两个ETFE气枕模型充气成形试验和数值模拟，得到了结构的膜面外形和应力分布及其变化规律.结果表明：对于三维裁切成形模型，气枕膜面外形的试验结果与数值模拟最大误差为4 mm，应力的最大值相差0.4 MPa；对于平面裁切成形模型，初次成形时的气枕膜面外形与应力分布的试验与数值相一致，随ETFE材料的徐变，膜面升高、应力减小，矢跨比由1/19增大为1/12.试验与分析验证了本文提出的成形设计方法.
Two design methods of ETFE cushion were presented which are the three-dimensional patterning based on zero-stress state and the flat-patterning based on nonlinearity of ETFE material. The state definitions and mechanical models were defined for the two methods, respectively. Experiments and numerical simulations were performed to obtain the shapes, stress distributions and the variations. It is found that, for the three-dimensional patterning model, the maximum difference of the shapes between experimental and numerical results is 4 mm and the difference of the stress distribution is 0.4 MPa. For the flat-patterning model, a good agreement between the experimental and numerical results is obtained for the initial shape and it is obtained that the stress distribution decreases while the shape and the ratio of rise to span increase due to the creep properties of ETFE materials. These findings have validated the proposed forming design methods.