鎖荷重式繊維引張試験機の試作とガラス繊維の強度分布について

抄録

This paper deals with the trial production of a chain-loading fiber tensometer and the statistical properties of the tensile strength of glass fibers with the nominal diameter of 13μm.
For the tensometer, the tensile load was increased by increasing the suspended length of the chain and a constant-stress-rate condition was realized. A newly introduced adhesive grip of the tensometer eliminated the breakage of fibers due to the gripping and also contributed the reduction in testing time. High accuracy in measuring fracture stress was achieved by using an appropriate loading chain.
The statistical properties of the tensile strength of glass fibers was clarified by a method used in reliability analysis. The probability of failure was calculated including censored data so as to achieve more accurate analysis. The strength distribution was well approximated by a normal or Weibull distribution function. Consequently, a statistical analysis can be done with a normal distribution function and a stochastic process theory can be discussed with a Weibull distribution function.
The mean strength of glass fibers with the nominal diameter of 13μm was 1.78GPa (gage length=100mm, stress rate=0.0153GPa/s). The coefficient of variation was 28.9%, but it should be considered that this value contains the variation of the sectional area of glass fibers.