Kapton膜材低温单轴循环拉伸力学性能研究

Research of uniaxial cyclic tensile mechanical properties of Kapton foils under low temperatures

为明晰充气天线反射面膜材的低温循环拉伸力学性能,对25μm厚的Kapton膜材进行了低温(20、0、-10、-40、-70℃)下的单轴循环拉伸试验,通过分析不同循环次数和温度下的应力-应变曲线,阐释了低温循环荷载作用下材料的受力机理与性能表征,分别建立了弹性模量与循环次数和温度的关系式,并获得了参量对棘轮应变以及滞回环面积的影响规律.试验结果表明:随着循环次数的增加,弹性模量逐步增大,滞回环面积减小;低温使得弹性模量显著提高,而滞回环面积减小;以最后一次循环加载后的结果来看,温度对膜材垂直方向的棘轮应变影响更大.研究所得结论可为极端温度场下的充气可展结构设计及在轨交变高低温测试提供参考.

In order to investigate the cyclic tensile mechanical properties of inflatable antenna reflector foil under low temperatures, uniaxial cyclic tensile tests for Kapton foils with the thickness of 25 μm under low temperatures(20, 0,-10,-40,-70 ℃) are conducted. By analyzing the stress-strain curves of different cyclic numbers and temperatures, the mechanical mechanism and properties characterizations of the material under cyclic loading at low temperature are explained. The equations relating elastic modulus to cyclic number and temperature are established. Influences of parameters on ratcheting strain and hysteresis loop area are also obtained. The experimental results show that with the increase of cyclic number, elastic modulus increases gradually yet hysteresis loop area declines. Low temperature makes the elastic modulus increase obviously yet the hysteresis loop area decreases. Based on the result of the last load loop, the temperature affects more on ratcheting strain in transverse direction of the foil. The conclusions can provide references for the inflatable deployable structure design under the extreme temperature field and the high-low temperature test of such structures in orbit.