摘要
在含表面缺陷试样的疲劳数据的基础上,提出了表面缺陷对疲劳寿命影响的尺寸参数,将其引入Walker寿命方程,建立了可以考虑表面缺陷尺寸特征的疲劳寿命预测方程。将该方程的寿命预测结果同考虑应力梯度的寿命预测方法的计算结果进行对比,两者在±3倍以内,验证了方法是准确可靠的。进而,将该方程应用于粉末高温合金涡轮盘的疲劳寿命预测中,获得了不同尺寸的表面缺陷对涡轮盘寿命的影响规律,其工程意义在于:依据涡轮盘危险位置的应力特征,能够给出存在缺陷时的疲劳寿命,可作为使用过程中的重要参考数据,一旦出现漏检的表面缺陷,也能够保证涡轮盘的安全工作。
On the basis of fatigue data of specimen with surface defects,the size parameter of surface defects was proposed,and introduced into the Walker life equation to study the effect of size of surface defects.And the life prediction results of the equation were compared with the calculation results of life prediction method considering the stress gradient.The scatter bands of the results of two models were within±3,indicating that the method is reliable.Then the equation was used in predicting the fatigue life of powder metallurgy turbine disk and obtaining the influence law of the surface defects with different sizes on the life of turbine disk.Its main engineering significance was that based on the stress characteristics of the dangerous position of turbine disk,the fatigue life with existence of the defect can be acquired.And even if the defects are not detected,it can ensure the safety in service period.
引文
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