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Tensile impact experiments of EC8.0-24×7 glass fiber bundles at different low tempera-tures T(14℃,-40℃ and-100℃)and strain rates ε were carried out,and complete stress-strain curveswere obtained.Within the range of the experiment temperatures and strain rates,it is found that the initialmodulus E,the ultimate strength σ_(max)and the unstable strain ε_b of the glass fiber bundles all increase withat an identical T.At an identical ε,with the decrease of T,E and σ_(max)increase; but ε_b increases when14℃>T>-40℃ and decreases when-40℃>T>-100℃.The strain-rate-and temperature-depen-dent bimodal Weibull statistical constitutive theory was adopted for the statistical analysis of the experimentalresults,and the Weibull parameters of single fiber were obtained.The results show that the bimodal Weibulldistribution function is suitable to represent the strength distribution of the glass fiber at low temperature anddifferent strain rates.The differences in the mechanical properties between EC8.0-24×7 and EC5.5-12×14 glass fiber bundles were also discussed.
Tensile impact experiments of EC8.0-24 × 7 glass fiber bundles at different low tempera ture T (14 ° C, -40 ° C and-100 ° C) and strain rates ε were carried out, and complete stress-strain curves were obtained. Whithin the range of the experiment temperatures and strain rates, it is found that the initialmodulus E, the ultimate strength σ_ (max) and the unstable strain ε_b of the glass fiber bundles all increase withat an identical T.At an identical ε, with the decrease of T, E and σ_ (max) increase; but ε_b increases when14 ° C> T> -40 ° C and when when -40 ° C> T> -100 ° C. The strain-rate-and temperature-depen- dent bimodal Weibull statistical constitutive theory was adopted for the statistical analysis of the experimental results, and the Weibull parameters of single fiber were. The results show that the bimodal Weibulldistribution function is suitable to represent the strength distribution of the glass fiber at low temperature and different strain rates. differences in. the mechanical proper ties between EC8.0-24 × 7 and EC5.5-12 × 14 glass fiber bundles were also discussed.