摘要
镍基高温合金的概率寿命预测要求模拟多种复杂随机现象。针对室温下航空发动机涡轮盘用GH4133B合金的疲劳裂纹扩展试验数据,采用Paris公式和含门槛值ΔKth的修正Paris公式,对不同应力比下的疲劳裂纹扩展速率进行概率预测。基于Paris公式和修正Paris公式的积分式计算不同存活概率P下的理论疲劳剩余寿命Nfp,并与试验疲劳剩余寿命Nft对比。结果表明,当P=50%时,基于修正Paris公式的Nfp与Nft吻合;当P=90%时,基于Paris公式和修正Paris公式的Nfp均与Nft吻合;当P=99%时,基于修正Paris公式的Nfp具有高可靠度。基于疲劳寿命试验数据的非线性回归分析绘制Nf-Fp,m-Fp,a曲面,引入参量γ表征平均载荷Fp,m和载荷幅值Fp,a对疲劳寿命Nf的影响,结果表明,在所研究的应力比范围内Fp,m对Nf影响大。
Probabilistic life prediction of nickel-base superalloy requires the modelling multiple complex random phenomena.The fatigue crack growth rates at various stress ratios are probabilistically predicted using the Paris formula and the modified Paris formula with threshold value ΔKth for fatigue crack growth test data of GH4133 B superalloy used in turbine disk of aero-engine at room temperature.The theoretic fatigue crack growth lives Nfp at various survival probabilities P predicted by integral based on the Paris formula and the modified Paris formula are calculated and compared with the test ones Nft.It is shown that Nfp obtained by integral based on the modified Paris formula is well fitted with Nft at P=50%,while both Nfp obtained by integral based on the Paris formula and that obtained by integral based on the modified Paris formula are all well fitted with Nft at P=90%,and Nfp obtained by integral based on the modified Paris formula possesses a high reliability at P=99%.A 3D Nf-Fp,m-Fp,a fatigue life surface are plotted based on the nonlinear regression analysis of fatigue life test data,and a parameter γ is introduced to characterize the effect of mean load Fp,m and load amplitude Fp,a on fatigue life Nf.It is suggested that the effect of Fp,m on Nf is larger than that of Fp,a on Nf.
出处
《机械工程学报》
EI
CAS
CSCD
北大核心
2015年第18期71-82,共12页
Journal of Mechanical Engineering
基金
湖南省教育厅重点资助项目(14A144)
关键词
涡轮盘
疲劳裂纹扩展
寿命预测
概率
应力比
turbine disk
fatigue crack propagation
life prediction
probability
stress ratio
作者简介
赵荣国，男，1973年出生，博士，教授，博士研究生导师，流变力学研究所副所长，湖南省青年骨干教师，湖南省应用力学学会常务理事。发表论文60余篇，获第三届中国流变学青年奖。主要研究方向为材料力学性能与破坏理论，结构静力特性与动力响应。E—mail：zhaorongguo@163．com.
刘亚风，男，1990年出生。主要研究方向为材料力学性能与破坏理论。E—mail：liuyafengxtu@sina．com
