Kapton薄膜高温单轴循环拉伸的力学性能

Cyclic tensile behaviors of Kapton foils under high temperatures

以25μm厚充气可展结构膜材Kapton(聚酰亚胺膜)为研究对象,选取6种温度工况(20,50,80,110,140,170℃)对其进行高温下单轴循环拉伸试验.通过分析不同循环次数和温度下的应力-应变数据,阐释了高温循环荷载作用下材料的受力机理与性能表征,分别建立了循环弹性模量与循环次数和温度的关系式,并获得了对棘轮应变以及滞回环面积等力学性能参数的影响规律.试验和分析结果表明:随着循环次数的增加,弹性模量逐步增大,滞回环面积减小;高温使得弹性模量显著降低,而滞回环面积增大;以最后一次循环加载后的结果来看,温度对TD(垂直膜材长度方向)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.

Aiming at the deployable structure material,we have conducted Kapton foils with the thickness of 25μm,uniaxial cyclic tensile tests under high temperatures(20℃,50℃,80℃,110℃,140℃,170℃).Via analyzing stress-strain curves of different cycles and temperatures,the mechanical mechanism and property characterizations of the material under cyclic loading at high temperatures are explained.We derive equations in which the cyclic elastic modulus is related to cycle numbers and temperatures.Influences on the ratcheting strain and the hysteresis-loop area are also analyzed.Experimental and analysis results show that,with the increase of cycles,the elastic modulus increases gradually,yet the hysteretic-loop area decreases.The occurrence of high temperatures prompts the elastic modulus to decease obviously,yet the hysteretic-loops area to increase.Based on the result of the last load loop,the temperature affects more on ratcheting strain in TD than in other directions.The proposed study can provide references for the deployable structure design under the extreme temperature field and the high-low temperature test of such structures in the orbit.