编辑: JZS133 | 2015-12-29 |
6 No.
2 June
2006 收稿日期 : 2005-
09 -
10 基金项目 : 国家自然科学基金项目(50471047, 50323003) 作者简介 : 李伟(1979 - ), 男 ,山东潍坊人 , 西南交通大学工学硕士研究生 , 从事材料、结构疲劳断裂研究 . 导师简介 : 鲁连涛(1965 - ), 男 ,黑龙江佳木斯人 , 西南交通大学副教授 . 文章编号 : 1671- 1637(2006)02 -
0017 -
05 高碳铬轴承钢超长寿命 S- N 关系的概率特性 李伟,鲁连涛 (西南交通大学 牵引动力国家重点实验室, 四川 成都 610031) 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1200 M Pa)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 . 关键词: 车辆工程;
高碳铬轴承钢;
疲劳寿命;
S- N 曲线;
概率模型 中图分类号 : U270 .
4 ;
O346 文献标识码: A Probabilistic character for S- N relations of high carbon- chromium bearing steel in super- long cycle life region Li Wei , Lu Lian- tao (S tate Key Laboratory of Traction Pow er, Southw est Jiaotong University, Chengdu 610031, Sichuan , China) 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 w ere fitted by general maximum likelihood method respectively , its probabilistic S- N curve models w ere established. Analysis result show s that the test data can be well fitted and the S- N curve can be w ell depicted w ith differentiating fatigue crack initiation mechanisms. It is discovered that w hen load level is above the fatigue limit (about
1 200 M Pa), 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.
2 tabs ,
5 figs ,
8 refs. Key words: vehicle engineering ;
high carbon- chromium bearing steel ;
fatigue life ;
S- N curve;
probabilistic model Author resume: Li Wei ( 1979- ), male , graduate student , 86- 28-
87600935 , lw _cy @sina. com ;
Lu Lian- tao(1965- ), male, associate professor, 86- 28-
87634355 , luliantao @ hotmail. com.
0 引言为了保证疲劳设计的可靠性, 通常对疲劳试验 得到 S- N 数据的分散性进行统计评估, 从而确定合 理的设计应力.一般钢铁材料的疲劳强度寿命和分 布符合对数正态分布或威布尔分布等, 而这种情况 下材料的裂纹萌生机制是单一的. 最近的超长寿命研究结果表明[ 1- 2] , 高强度钢 的疲劳裂纹的萌生出现两种机制 : 一种是高应力幅 短寿命区出现的表面裂纹萌生机制 ;