芳纶编织物在高载荷下的使用寿命预测

Prediction of service life of aramid woven fabric under high load

针对预测芳纶绳带在降落伞上的使用寿命常采用半经验的方法,缺乏理论依据。通过研究高载荷下25-600型芳纶1414绳带蠕变行为和抗冲击性能,分别得到芳纶1414绳带载荷大小与蠕变断裂时间之间的拟合曲线和冲击强度与冲击次数之间的拟合曲线,用于预测其在高载荷下的使用寿命,并测定绳带试验前后的取向度和结晶度。结果表明:在蠕变过程中载荷大小与蠕变时间对数呈函数关系,其中单层和单圈两层绳带的拟合方程分别为ln t=33.65-0.33σ和ln t=32.45-0.31σ;冲击模型的斜率与截距均与蠕变模型呈2倍的关系,当样品承受相同载荷时,蠕变断裂时间对数与冲击次数之间的关系为ln t=An-B,即可用冲击次数预测绳带的蠕变断裂时间,反之亦然。芳纶1414绳带蠕变和冲击前后的取向度与结晶度表明,在相同载荷下,蠕变和冲击对绳带的损伤效果相同,这进一步证明25-600型芳纶1414绳带蠕变性能与冲击性能之间高度联系。

The semi-empirical method is used to predict the service life of aramid tape in parachute,but lacks of theoretical basis.In this paper,the creep behavior and impact resistance of type 25-600 Aramid 1414 tape under high loads were used to fit the curve of the load size and creep breaking time and the curve of the impact strength and the number of impact tests,respectively,which can be used to predict the service life of aramid tape under high load,and the orientation and crystallinity of the tape before and after the test were measured.The results show that there is a functional relationship between the load and the logarithm of creep time during the creep process,and the fitting equations of single-layer and single-loop two-layer tapes are lnt=33.65-0.33σand lnt=32.45-0.31σ,respectively.The slope and intercept of the impact model are twice those of the creep model.When the sample is under the same load,the relation between the logarithm of creep breaking time and the number of impact tests is lnt=An-B,and the number of impact tests can be used to predict the creep breaking time of the tape,and vice versa.The creep and orientation and crystallinity of Aramid 1414 tape before and after impact tests indicate that under the same load,creep and impact have the same damage effect on the tape,which further proves that there is a high correlation between the creep and impact properties of type 25-600 Aramid 1414 tape.