STRAIN RATE AND TEMPERATURE DEPENDENCE OF MECHANICAL PROPERTIESOF HIGH-STRENGTH AND HIGH-MODULUS POLYETHYLENE FIBER YARNS

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.