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为了对高碳铬轴承钢疲劳S-N(应力-寿命)试验数据做出正确评估,采用广义极大似然法对全部S-N数据和区分裂纹萌生机制下的S-N数据分别进行了拟合,建立了概率S-N曲线模型。结果表明,在区分裂纹萌生机制下,能较好地拟合试验数据和描述S-N曲线形式;在疲劳极限(大约1 200 MPa)以上的部分要选用裂纹萌生于表面的S-N曲线形式,对于疲劳极限以下的要选用裂纹萌生于内部的S-N曲线形式;同时验证了广义极大似然法能较好地测定该材料的概率S-N曲线(由P-S-N曲线、C-S-N曲线和P-C-S-N曲线组成)和表征该材料超长寿命S-N关系的概率特性。
In order to correctly evaluate the fatigue SN test data of high-carbon chromium bearing steel, the generalized maximum likelihood method was used to fit the SN data under all SN data and the discriminating crack initiation mechanism respectively, and the probability SN curve model. The results show that under the mechanism of distinguishing crack initiation, the experimental data can be well fitted and the SN curve form can be well fitted. For the part above the fatigue limit (about 1 200 MPa), the SN curve with crack initiation surface is chosen. For the fatigue limit In the following, we choose the SN curve with internal crack initiation. The generalized maximum likelihood method is also used to determine the probability SN curve (composed of PSN curve, CSN curve and PCSN curve) Probability characteristics of long life SN relationship.