Probabilistic character for S-N relations of high carbon-chromium bearing steel in super-long cycle life region
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摘要: 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。Abstract: In order to accurately evaluate the fatigue S-N (stress-life) test data of high carbon-chromium bearing steel in super-long cycle life region, the entire S-N data and the S-N data based on differentiating fatigue crack initiation mechanisms were fitted by general maximum likelihood method respectively, its probabilistic S-N curve models were established. Analysis result shows that the test data can be well fitted and the S-N curve can be well depicted with differentiating fatigue crack initiation mechanisms. It is discovered that when load level is above the fatigue limit (about 1200 MPa), the S-N curve that fatigue crack initiates from surface should be chosen, on the contrary, the S-N curve that fatigue crack initiates from subsurface should be chosen. It is proved that the material's probabilistic S-N curves, including survival probability-stress-life curves, confidence stress-life curves and survival probability-confidence-stress-life curves, can be determined, and the probabilistic characters for the S-N relations in super-long cycle life region can be depicted by general maximum likelihood method.
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表 1 化学成分
Table 1. Chemical composition
元素 C Si Mn Cr Cu Ni Mo P S 含量/% 1.010 0.230 0.360 1.450 0.060 0.040 0.020 0.012 0.007 表 2 疲劳试验数据
Table 2. Fatigue test data
序号(i) 应力/MPa 寿命/cycle 序号(i) 应力/MPa 寿命/cycle 1 1 700 4 480 27 1 250 65 990 2 6 100 28 128 800 3 6 840 *29 2 486 740 4 1 600 5 200 *30 4 983 540 5 7 790 *31 8 950 470 6 10 000 *32 10 325 090 7 1 500 8 990 *33 11 730 550 8 14 400 *34 26 058 040 9 34 700 35 1 200 125 280 *10 247 000 36 269 920 *11 609 000 37 672 410 12 1 400 13 460 *38 8 771 540 13 15 900 *39 19 548 550 14 17 220 *40 35 175 720 15 40 800 *41 41 502 050 *16 839 140 *42 43 386 180 *17 1 540 000 *43 61 683 430 *18 4 970 760 *44 1 150 23 276 820 19 1 300 15 360 *45 47 700 000 20 22 670 *46 1 100 66 744 290 21 39 830 *47 96 100 000 *22 2 050 180 *48 138 813 570 *23 2 480 000 *49 1 000 101 000 000 *24 3 870 000 *50 137 883 470 25 1 250 40 560 *51 900 1 050 000 000 26 52 430 *52 1 234 110 000 注: 带“*”的序号表示裂纹萌生于内部的试验数据。 -
[1] Sakai T, Sato Y, Oguma N. Characteristics S-N properties of high carbon chromium bearing steel under axial loading in longlife fatigue[J]. Fatigue and Fracture of Engineering Materials and Structures, 2002, 25(1): 765-773. [2] Shiozawa K, Lu L, Ishihara S. S-N curve characteristics and subsurface crack initiation behaviour in ultra-long life fatigue of a high carbon-chromium bearing steel[J]. Fatigue and Fracture of Engineering Materials and Structures, 2001, 24(1): 781-790. [3] 高镇同, 熊峻江. 疲劳可靠性[M]. 北京: 北京航空航天大学出版社, 2000. [4] 赵永翔. 有限数据下结构疲劳可靠性设计曲线的统计模型[J]. 核动力工程, 2002, 23(3): 46-49. https://www.cnki.com.cn/Article/CJFDTOTAL-HDLG200203008.htmZhao Yong-xiang. Statistical model for determining the structural fatigue reliability design curve under limited data[J]. Nuclear Power Engineering, 2002, 23(3): 46-49. (in Chinese) https://www.cnki.com.cn/Article/CJFDTOTAL-HDLG200203008.htm [5] 杨冰, 赵永翔, 邬平波, 等. 16MnR钢焊接头的延拓概率疲劳S-N曲线[J]. 交通运输工程学报, 2004, 4(4): 25-29. http://transport.chd.edu.cn/article/id/200404007Yang Bing, Zhao Yong-xiang, Wu Ping-bo, et al. Extrapolation of probabilistic fatigue S-N curves on 16MnR steel weld joint [J]. Journal of Traffic and Transportation Engineering, 2004, 4(4): 25-29. (in Chinese) http://transport.chd.edu.cn/article/id/200404007 [6] 赵永翔, 王金诺, 高庆. P-S-N曲线及其置信限参数估计的统一常规方法[J]. 机械强度, 2000, 22(3): 217-221. doi: 10.3321/j.issn:1001-9669.2000.03.017Zhao Yong-xiang, Wang Jin-nuo, Gao Qing. A united conventional method for estimating P-S-N curves and their confidence bounds[J]. Journal of Mechanical Strength, 2000, 22(3): 217-221. (in Chinese) doi: 10.3321/j.issn:1001-9669.2000.03.017 [7] Masaru Z, Tetsusei K, Satoshi H. On evaluation method of the data for super-long life fatigue property[J]. The Society of Material Science, 2001, 50(2): 158-162. doi: 10.2472/jsms.50.158 [8] 赵永翔, 高庆, 王金诺. 估计三种常用应力-寿命模型概率设计S-N曲线的统一方法[J]. 核动力工程, 2001, 22(1): 42-52. doi: 10.3969/j.issn.0258-0926.2001.01.010Zhao Yong-xiang, Gao Qing, Wang Jin-nuo. Unified approach for estimating the probabilistic design S-N curves of three commonly used fatigue stress life models[J]. Nuclear Power Engineering, 2001, 22(1): 42-52. (in Chinese) doi: 10.3969/j.issn.0258-0926.2001.01.010