声脉冲传播法测定纤维动态弹性模量方法实证与标准化

Measurement of dynamic elastic modulus of fiber by sonic-pulse propagation method and its standardization verification

采用声速法纤维取向度/动态弹性模量测定仪,以涤纶单丝为试样,通过变换试样预张力和换能器隔距,分别测定对应的声波旅行时间。结果表明:不同预张力下所测得的声波旅行时间-换能器隔距散点数据与最小二乘法拟合直线高度相符,并可由外推法计算仪器系统的延迟时间T;、纤维中的声速C和动态弹性模量E的准确可靠值,且可根据已知的无规取向声速值C;计算赫尔曼取向因子F和取向角θ;延迟时间与换能器隔距和试样预张力都相关,而不是理论上的固有不变;倍长法计算优选的预张力为0.09~0.18 cN/dtex,换能器隔距为100 mm和200 mm,适合只需相对比较的工业应用和教学演示,而外推法更适于精确定量科研。

Using a fiber orientation degree/dynamic elastic modulus tester with sonic velocity method,taking polyester monofilament as a sample, the corresponding sonic wave travel time is measured through changing the sample pre-tension and transducer spacing. The results show that the measured sonic wave travel time-transducer spacing scatter data under different pre-tensions are consistent with the fitting straight line via the least square method, and which shows that the extrapolation method can calculate the accurate and reliable values of the delay time T;of the instrument system, the sonic velocity C in the fiber and the dynamic elastic modulus E. Furthermore, the Hermans orientation factor F and orientation angle θcan be calculated according to the given random orientation sonic velocity C;. The delay time is obviously related to the transducer spacing, rather than the inherent invariance in theory. The optimal transducer spacing calculated via the double-length method is 100 mm and 200 mm, and the pre-tension is 0.09~0.18 cN/dtex. It is suitable for industrial application and teaching demonstration requiring only relative comparison, while the extrapolation method is more suitable for accurate quantitative scientific research.