セラミックスの疲労寿命分布からのき裂進展速度の推定

概要

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A statistical method for lifetime prediction is important for determination of the fatigue behavior of ceramics, because the lifetime data of ceramic materials are scattered. In this study, the lifetime data of silicon nitride ceramics were obtained using piezo bimorph fatigue equipment with stress ratio R =0.1 and frequency f=150 Hz (sine wave) . A statistical method for estimating the relationship between the initial applied stress intensity factor (K_<Imax>) and the fatigue lifetime (N_f) was proposed. By this method, a single K_<Imax-N_f diagram was obtained even if the maximum applied stress levels had been different in cyclic fatigue testing. It was proved that the distribution of the fatigue lifetime was determined by the distribution of initial cracks. The crack growth rate (K_I-V) diagram was estimated using Fett's method from the K_<Imax>-N_f diagram. Acceleration of the crack growth rate in natural cracks was observed in the region of lower applied stress intensities.
社団法人日本機械学会の論文
1993-05-25