応力および破壊位置の確率論によるセラミックスの曲げ強度解析

概要

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In this report we analysed the data of 3-point bending tests on Si_3N_4 and PSZ rectangular bar specimens and ZrO_2 round bar specimens. The strength distriburions of Si_3N_4 and PSZ and that or ZrO_2 were represented by the multi-modal weibull distribution and 2-parameter Weibull distribution (mono-modal), respectively. The parameter of the former wre estimated with the molti-step masimum likelihood method, and those of th latter with the least wquare method. Using these parameters, the true stress (stress at the fracture origin) distributions were calculated on the basis of the statistical theory of stress and fracture location. As a result of comparison of the calculated distributions and experimental data,it was found that the both distributions showed good agreement. Furthermore on the ZrO_2 round bar specimens other bending tests were carried out, varying the specimen size and the loading method. Weibull moduli obtained in the tests were not constant. There was a tendency that they increased as the effective size decreased. We discussed the reason of this change, considering the experimental relationship between the crack size and the fracture strength.
社団法人日本材料学会の論文
1989-07-15