高温低周应变疲劳的三参数幂函数能量方法研究

A Method Based on Energy and Three-parameter Power Function for Low Cycle Fatigue

对Manson-Coffin方程、拉伸滞后能寿命模型和三参数幂函数公式进行了应用研究,提出了三参数幂函数能量方法,并用某高温合金900℃低周疲劳数据进行了验证研究。通过寿命预测分散带和标准差的比较发现:三参数幂函数能量方法的低周疲劳寿命预测能力较Manson-Coffin方程和三参数幂函数公式的寿命预测能力有较大的提高;用三参数幂函数能量方法确定的循环应力-应变曲线比用Manson-Coffin方程处理得到的塑性应变分量确定的循环应力-应变曲线更能反映低周疲劳过程中应力和应变之间的关系。

The Manson-Coffin equation, ostergren model and three-parameter power function for low cycle fatigue（LCF） are investigated, and a three-parameter strain energy function is developed for high temperature low cycle fatigue. The new method is validated by using a high temperature superalloy at 900℃. The results of low cycle fatigue life prediction shows that the life prediction capability of three-parameter strain energy function is better than those of Manson-Coffin equation and three-parameter power function, and the cyclic stress-strain curves gained by three-parameter strain energy function reflect better the relationship of stress and strain in low cycle fatigue than Manson-Coffin equation does.