改进的统一疲劳裂纹扩展速率预报模型对合金在常幅载荷下普遍适用性的研究

精确预报金属结构的疲劳对确保结构安全及指导结构设计与维修具有重要的意义.作者们基于McEvily模型提出了一个改进的统一疲劳裂纹扩展速率模型,其将疲劳裂纹扩展的三个扩展区域统一起来,并能解释更多的疲劳试验现象.文中对该模型进行了详细阐述,同时对模型参数的工程预报方法进行了讨论.为了进一步检验本模型的可靠性,还对不同载荷比下各种材料疲劳裂纹扩展率的预报结果与实验结果进行了对比,对比结果证明了该模型的准确性及其在常幅载荷下对不同材料的普遍适用性.

Applicability of the Improved Crack Growth Rate Model for a Wide Range of Alloys under Constant Amplitude Load

The precise fatigue life prediction is very necessary to ensure the safety of marine struc-tures and guide economic design and maintenance.An improved crack growth rate model which can unify three regions of crack growth rate curve and explain more fatigue phenomena observed in tests was established based on McEvily's model.In this paper,the improved crack growth rate mod-el is further specified,and the engineering methods to determine its parameters for practicability are discussed. Finally, comparisons between the predicted crack growth rate curves under different load ratios with their corresponding experimental data for wide range of alloys such as aluminum alloy, titanium alloy and steel are carried out, showing that the improved crack growth rate model has good accuracy and wide applicability under constant amplitude load.