摘要
基于材料裂纹扩展阻力曲线(R曲线)及裂纹扩展能量释放率理论,定义疲劳载荷下的有效能量释放率(G eff)为疲劳裂纹完全张开后用于裂纹扩展的能量,与同一载荷循环中由裂纹扩展阻力曲线表征的消耗能相等,提出了一种能够反映裂纹扩展物理本质的疲劳裂纹扩展寿命预测模型。该模型可以计算每一载荷循环中的裂纹扩展量,进而预测疲劳裂纹扩展寿命。通过试验测定了7050-T7451铝合金板材的R曲线,采用最小二乘法拟合获得到了R曲线表达式。运用本模型对同种材料耳片结构的裂纹扩展寿命进行了预测,与试验结果吻合较好,优于传统Paris模型的预测结果。
Based on the R-curve and crack propagation energy release rate theory,the effective energy release rate Geff was narrated as the energy that makes the opened crack grow and is equal to the dissipated energy represented by R-curve in the same load cycle.The fatigue life prediction model which can reflect the physical essence of crack propagation was proposed.The fatigue crack propagation life can be predicted by adding up the length of crack grows in each load cycle using the model.The R-curve of 7050-T7451 aluminum alloy plate was determined and the expression was obtained by using the least square method.The crack growth test of attachment lugs with the same material was carried out.The fatigue crack propagation life of the test pieces was predicted by using the present model and compared with the test data.The results show that the model based on material＇s R-curve can predict fatigue crack growth life more accurately than Paris Model.
出处
《航空材料学报》
EI
CAS
CSCD
北大核心
2013年第6期76-80,共5页
Journal of Aeronautical Materials
基金
国家"863"计划(2009AA04Z406)
国家自然科学基金(50975284)
陕西省自然科学基金(SJ08E107)
关键词
疲劳裂纹扩展
R曲线
能量释放率
耳片结构
损伤容限
fatigue crack growth
R-curve
energy release rate
attachment lug
damage tolerance
作者简介
伍黎明（1985-）,男,博士研究生,主要从事飞机结构强度与使用寿命研究,（E-mail）wuliming1985@foxmail.com
何宇廷（1966-）,男,博士,教授,主要从事飞行器结构寿命可靠性及安全性、结构健康监控等研究,（E-mail）hyt666@tom.com.
