纱线的应力松弛性能

以标准线性固体模型为基础,利用玻尔兹曼叠加原理对纱线在拉伸松弛过程中的力学行为进行分析,建立纱线应力松弛的理论方程。在应变一定、拉伸速度不同情况下和拉伸速度一定、不同应变条件下分别对涤/粘纱和竹浆纤维/棉纱进行拉伸应力松弛实验,求得纱线在各种情况下的应力松弛回归方程及其相关系数,理论计算和实测结果在拉伸和松弛阶段都符合得很好。实验结果表明:该模型能够很好地模拟纱线在小应变下的松弛性能;在其他条件相同的情况下,拉伸速度越大或纱线应变越大,纱线的松弛时间越短,松弛现象越明显。

Stress relaxation properties of yarns

The stress relaxation properties of yarns are studied.Based on the superposition principle of Boltzman,the elongation-stress relaxation process of yarns is analyzed using the standard linear solid model.Theoretical equations of the elongation-stress relaxation process are deduced.The elongation-stress relaxation experiments of polyester/rayon and regenerated bamboo fiber/cotton blended yarns are performed under such conditions as constant stress and different elongation rates and constant elongation rate and different stresses.The regressive equations of stress relaxation and correlation coefficients of the yarns are calculated.Theoretical expectations display very good agreement with the experiment observations.It indicates that the standard linear solid model can be used to describe the stress relaxation properties of yarns under lower strain conditions.It is found from the experimental and theoretical results that the higher the strain or the elongation rate,the lower the relaxation time and more apparent the relaxation phenomenon.