高强高模聚乙烯纤维力学性能的应变率和温度效应
STRAIN RATE AND TEMPERATURE DEPENDENCE OF MECHANICAL PROPERTIESOF HIGH-STRENGTH AND HIGH-MODULUS POLYETHYLENE FIBER YARNS
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摘要: 利用MTS810材料试验机、旋转盘式杆-杆型冲击拉伸装置和温度控制箱,在温度20℃~110℃、应变率为0.001/s~700/s范围内,对高强高模聚乙烯纤维束进行了准静态和高应变率冲击拉伸实验,得到了不同温度、不同应变率时纤维束的应力-应变曲线。结果表明:高强高模聚乙烯纤维束的初始弹性模量具有应变率和温度相关的特性,随应变率提高而增加,随温度提高而下降;在常温下,破坏应力从准静态到动态,具有明显的应变率相关性,随应变率提高而增加,但在20℃~110℃范围内、高应变率下,对应变率变化不敏感;失稳应变也具有应变率和温度相关的特性,随应变率提高而减小,随温度提高而增大。在高应变率下,断裂应变能密度主要由初始弹性模量和失稳应变共同决定,受温度效应和应变率效应的综合影响。Abstract: The quasi-static and high strain rate tensile impact experiments on the high-strength and high-modulus polyethylene fiber (HSM-PE) yarns were performed at 20℃~110℃ and strain rate 0.001/s~700/s by means of MTS 810, rotating disk bar-bar tensile impact apparatus and temperature-controlled box, and the stress-strain curves of fiber yarns at different temperatures and different strain rates were obtained. The experimental results indicate that the initial elastic modulus of Dyneema SK65 fiber yarns is rate-dependent and temperature-dependent:it increases with the rising of strain rate and decreases with the rising of testing temperature. The strength of the fiber yarns tested from quasi-static to dynamic is rate-dependent at the normal temperature, but it is rate-insensitive at high strain rate and at 20℃~110℃. The unstable strain is also rate-dependent and temperature-dependent: it decreases with the rising of the strain rate and increases with the rising of the testing temperature. The fracture strain energy density at the high strain rate is mainly determined by the initial elastic modulus and the unstable strain and affected by the temperature and the strain rate.