为分析铝合金结构拱形ETFE(乙烯一四氟乙烯热塑性聚合物)膜屋面的抗风性能,提高其设计的安全性,该文根据单轴拉伸试验数据,确定了ETFE薄膜材料的力学参数和应力应变关系;基于几何非线性有限元理论,推导了膜单元的基本方程;利用大型通用有限元软件ANSYS,采用支座提升法对骨架式拱形ETFE屋面进行了找形分析,建立了用于荷载分析的计算模型;对拱形ETFE屋面在风荷载工况下进行了算例分析,计算了膜面主应力分布和变形特征;分析了不同膜面预应力水平对承载性的影响。分析结果表明,风荷载主要影响ETFE膜屋面第一主应力的分布,适当增加膜面预应力可以显著提高其整体刚度和承载力。研究结论为铝合金温室拱形ETFE屋面的抗风计算分析和施工提供了参考。
In order to analyze the wind resistance performance of the ETFE membrane roof in aluminum alloy greenhouse and improve the design safety, mechanics parameters and stress-strain relationship for ETFE membrane were obtained based on uniaxial tensile test data. The basic equations of membrane element were derived based on the geometrical nonlinear finite element theory. The computation model for loading case analysis was established, after determined the initial shape of ETFE membrane used in arch framed roof by means of pedestal-shifting method through general finite analytic software-ANSYS. Membrane surface principal stress distribution and deformation characteristics of an example project were calculated under the condition' of wind load, and the effects of different membrane surface prestress levels on load-bearing capacity were analyzed. Analysis results showed that the wind load mainly affected the first principal stress distribution of the arch ETFE membrane roof, and the proper increase of prestress could significantly improve its global stiffness and load-bearing capacity. This research provides references for arch ETFE membrane roof wind-resistance computational analysis and fabrication of the multi-span aluminum alloy greenhouse.