基于损伤力学的粉末高温合金FGH96疲劳寿命预测

以粉末高温合金FGH96为研究对象，提出采用损伤力学理论来建立寿命预测模型。对于不同夹杂物特征，粉末高温合金裂纹萌生有不同的表征参量，其数值变化为裂纹萌生的寿命预测提供思路。对粉末高温合金寿命预测的研究现状进行分析，然后利用损伤演变方程建立寿命预测模型；使用有限元软件（ANSYS）分别模拟夹杂物的不同位置、不同尺寸以及不同形状对裂纹萌生的影响，得到相应的损伤参量分布云图。将得到的损伤参量代入计算模型，得到疲劳寿命计算结果，与实验结果进行对比，证明疲劳寿命预测模型的有效性。结果表明:损伤参量Y能较好地表征材料的低周疲劳损伤；在不同的实验条件（温度、应变范围和应变比）下，所建立的粉末合金FGH96疲劳寿命预测模型都能较好地反映夹杂物对粉末高温合金疲劳寿命的影响。

Fatigue Life Prediction of Powder Superalloy FGH96 Basedon Damage Mechanics

Taking powder superalloy FGH96 as the research object, a new life prediction model method based on damage mechanics theory was proposed. For different inclusion characteristics, the crack initiation of powder superalloy has different characterization parameters, and its numerical changes provide an idea for the life prediction of crack initiation. In the present work, the current research status of the life prediction of powder superalloys was analyzed, and then the damage evolution equation was used to formulate the life prediction model. The finite element software (ANSYS) was used to simulate the influence of different positions, sizes and shapes of inclusions on crack initiation, and the corresponding damage parameter distribution cloud maps were obtained. Substituting the obtained damage parameters into the calculation model, the fatigue life calculation results were obtained. Comparing the calculation results with experimental ones, the validity of the fatigue life prediction model was proved. The results showed that the damage parameter Y can well characterize the low cycle fatigue damage of the material; Under different experimental conditions (temperature, strain range and strain ratio), the established fatigue life prediction model of powder alloy FGH96 can well reflect the effect of inclusions on the fatigue life of powder superalloy.