摘要
根据旋转弯曲圆棒疲劳断口分析 ,给出了裂纹几何参量及应力强度因子随裂纹扩展的变化规律。采用考虑三维应力约束效应的断裂力学理论及常幅载荷下材料的疲劳裂纹扩展 da/d N～ΔK曲线 ,得到了独立于试件几何形状和应力比的材料 da/d N～ΔKeff基准数据。结合断口分析所得的应力强度因子以及材料 da/d N～ΔKeff数据 ,对三种旋转弯曲圆棒 S-N(应力 -疲劳寿命 )曲线进行了预测。结果表明 ,本文预测的疲劳 S-N曲线和试验的结果较为吻合。本文的 S-N曲线断裂力学预测方法对确定结构全寿命具有实际指导意义 。
By investigation of the fatigue fractography of round bars under rotational bending, the geometrical shapes of the crack during the fatigue crack growth are obtained. Stress intensity factors (SIF) can be determined for the crack shape. Using the advanced three-dimensional fracture theory and da/dN~ΔK curves of the materials under constant amplitude loading, the material base line of da/dN~ΔK eff is found to be independent for geometrical shape and stress ratio. With the obtained SIFs and da/dN~ΔK eff base line, fatigue stress-life (S-N) curves for the round bars under rotational bending are predicted. It is shown that the predicted S-N curves are in good agreement with experimental data for all the materials in this study. Results highlight the possibility to predict the S-N curves by the three-dimensional fracture methodology.
出处
《南京航空航天大学学报》
EI
CAS
CSCD
北大核心
2002年第3期216-220,共5页
Journal of Nanjing University of Aeronautics & Astronautics
基金
航空科学基金 (编号 :0 1 B5 2 0 1 2 )资助项目
