循环加载处理对聚氯乙烯涂层膜材料蠕变性能的影响

为深入研究膜材料在受力过程中的蠕变作用机制,以聚氯乙烯涂层膜材料为研究对象,对其历经循环加载过程后的蠕变性能进行测试,分析了循环加载次数、循环峰值应力与循环加载速率对蠕变性能及初始变形保持能力的影响规律。研究结果表明:经不同循环加载过程后的涂层膜材料蠕变机制基本一致,蠕变性能及对初始变形的保持能力不仅受循环加载次数、循环峰值应力的影响,同时还与循环加载速率密切相关;对于聚氯乙烯涂层膜材料,增加循环加载次数、提高循环应力峰值、降低循环加载速率,均有助于提高蠕变过程对初始变形的保持能力,减少膜结构建筑后期维护工作量,但会延长循环加载阶段的耗时,增加施工过程预加张力阶段的工作量。

Effect of cyclic loading treatment on creep behavior of polyvinyl chloride coated membrane

To further investigate the mechanism of loading process on the creep properties of coated membrane, the creep behavior of polyvinyl chloride (PVC) coated membrane after cyclic loading were evaluated, and the effects of cyclic number, peak cyclic stress and cyclic loading rate on the creep behavior and ability to retain the initial deformation in creep process were also analyzed. The results show that the creep mechanism of the coated membrane after different cyclic loading processes are basically the same, the creep behavior and ability to retain the initial deformation in creep process are governed by cyclic number, peak cyclic stress, and the cyclic loading rate. For the PVC coated membrane, increasing loading cycles, improving cyclic peak stress and decreasing loading rate are beneficial for improving the ability to retain the initial deformation in the creep process,and for reducing the maintenance workload of the membrane structure during its service time. However, it would prolong the cyclic loading period and increase the workload during the pretension stage in the construction process.