乙烯-四氟乙烯薄膜徐变特性的试验分析

Experimental Study of Creep Properties of Ethylene Tetrafluoroethylene Foil

对12组250μm厚的乙烯-四氟乙烯(ETFE)薄膜在40~80℃时进行了不同温度和应力下的徐变试验.对试验数据进行对数拟合,分析了拟合参数随试验条件的变化规律,得出考虑加载应力和温度的函数关系式,用以描述ETFE薄膜在不同温度和应力下的徐变性能.该函数关系式对后续分析ETFE薄膜力学性能和长期荷载作用下的结构性能有重要作用.试验和分析结果表明,ETFE薄膜的徐变量随加载应力的增大和温度的升高而明显增大,且呈非线性关系;温度小于40℃且应力小于6MPa时,材料的徐变量较小且增加缓慢;40℃以上或较高应力状态下,徐变显著.

Creep tests on twelve groups of ethylene tetrafluoroethylene(ETFE)foil samples of 250μm thick were conducted at different temperatures and stresses.According to the test results,this paper employed the logarithmic fitting of time-deformation relations,and analyzed the parameter variations under different test conditions.The relationship between creep strain,stress and temperature was established and used to describe the creep properties of ETFE foils.It was found that a large creep strain existed at high temperature or large stress,and that the relationship between strain,stress and temperature was nonlinear.Moreover,the creep strain kept small if the temperature was under 40 ℃ and the stress was under 6 MPa while large creep strain was observed at high temperature and stress.