计及温度与应变率效应的超高分子量聚乙烯纤维束的拉伸力学性能

Tensile Mechanical Properties of Ultra-High Molecular Weight Polyethylene Fiber Bundles with Temperature and Strain Rate Effect

文中针对超高分子量聚乙烯(UHMWPE)纤维束在计及温度(-60~80℃)和应变率(1×10^(-5)~3.3×10^(-2)s^(-1))的25种工况下,基于轴向拉伸实验数据,研究了UHMWPE纤维束力学性能的温度和应变率效应及其破坏模式。结果表明,UHMWPE纤维束的力学性能具有一定的应变率和温度效应,但后者具备更为强大的影响力,其使UHMWPE纤维束在温度高于50℃时强度产生显著下降;此外,低温在提升UHMWPE纤维束拉伸强度的同时也会削弱其力学性能的应变率效应,在-40~-60℃范围内,UHMWPE纤维束拉伸强度和失效应变基本不受应变率影响。在UHMWPE纤维束的损伤破坏模式研究中发现,在脆-韧性转变存在的温度区间内(25~80℃),转变发生的临界应变率与温度之间具有密切联系,温度每升高约30℃,临界应变率就会提升1个量级。

Apreparation method of ultra-high molecular weight polyethylene(UHMWPE)fiber bundle samples was designed to effectively prevent fiber pull out and root shear fracture of samples.Based on the experimental data of axial tensile test,the temperature and strain rate effects of mechanical properties of UHMWPE fiber bundles and their failure modes were investigated under 25 kinds of working conditions including temperature(-60~80℃)and strain rate(1×10^(-5)~3.3×10^(-2)s^(-1)).The results show that the mechanical properties of UHMWPE fiber bundles have certain strain rate and temperature effects,but the latter has a more powerful influence,which makes the strength of UHMWPE fiber bundles decrease significantly when the temperature is higher than 50℃.In addition,low temperature can improve the tensile strength of UHMWPE fiber bundles and weaken the strain rate effect of mechanical properties.In the range of-40℃to-60℃,the tensile strength and failure strain of UHMWPE fiber bundles are not affected by strain rate.In the investigation of damage and destruction modes of UHMWPE fiber bundles,it is found that the critical strain rate of brittle-tough transition is closely related to temperature in the temperature range of 25~80℃,and the critical strain rate will increase by an order of magnitude every time the temperature increases by about 30℃.