2013 年 62 巻 10 号 p. 640-647
The strength evaluation of glass short fiber reinforced phenolic resin (G/P) made by transfer forming was studied in this paper. In order to investigate the strength of G/P in comparison with various volume fiber content Vf (=0%, 20%, 50%), three kinds of basic strength test (3-point bending, 4-point bending, and tensile test) at room temperature were carried out. The Weibull statistic theory was applied to evaluating size effect of each specimen. The strength distribution was consistent with the Weibull chart, and obtained Weibull coefficients, m, were ranged from 5.8 to 17.6. The effective volume, Veff, and Weibull coefficients m0 were estimated based on effective volume theory. Relationships between strength, σf, and effective volume, Veff, shows good agreement with the equation of the effective volume theory onto the double logarithmic chart. To verify the efficiency of the effective volume theory, open hole specimen (OH specimen) of G/P were subjected to tensile test. Veff of OH specimens was calculated by integrating the stress distribution, which obtained by finite element analysis, with the volume. And then, the distribution of fracture probabilities was predicted by Weibull statistical theory. As a result of tensile test for OH specimens, it was concluded that the prediction method by effective volume theory based on Weibull statistical theory was applicable to strength evaluation of G/P.