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对边长为3.74m的三角形ETFE双层气枕进行充气和膜面堆载试验,利用激光位移计对上下层8个测点的膜面高度进行实时测量,并与数值模拟结果对比分析.研究了三角形ETFE双层气枕的成形过程及风、雪荷载作用下的力学性能,验证了基于单轴拉伸试验所得材料力学参数的正确性和利用非线性有限单元法进行ETFE气枕分析的适用性.研究表明:(1)内压或外荷载作用下,三角形ETFE气枕膜面变形对称性较好,膜面高度随着内压、外荷载的增大呈线性增加或减小规律;(2)在风、雪荷载作用下,三角形ETFE气枕内接圆区域膜面应力较大且分布均匀,角部是低应力区,容易形成垂直于对角线的褶皱;(3)在风、雪荷载作用下,膜面应力小于ETFE第一屈服强度,气枕处于线弹性工作状态,三角形ETFE气枕具有较好的抵抗外部荷载作用的能力.
The triangular ETFE bolster with side edge length of 3.74m was used for inflating and membrane surface loading test, and the height of membrane surface at the upper and lower measuring points was measured by laser displacement meter in real time and compared with the numerical simulation results. The forming process of the triangle ETFE double-layer cushion and the mechanical properties under the wind and snow loads validated the correctness of the mechanical parameters of the material based on the uniaxial tensile test and the application of the non-linear finite element method for the ETFE cushion analysis The results show that: (1) under the action of internal pressure or external load, the symmetry of triangle ETFE air pillow is good, and the membrane height increases or decreases linearly with the increase of internal pressure and external load; 2) under wind and snow loads, the membrane surface of the triangle ETFE gas pillow has large and uniform stress distribution on the membrane surface, and the corner is a low-stress zone, which is easy to form the fold perpendicular to the diagonal line. (3) Under the action of snow load, the membrane surface stress is less than the first yield strength of ETFE, and the air cushion is in a linear elastic working state. The triangular ETFE air cushion has a better capability of resisting external load.