基于三参数幂函数的低周疲劳寿命预测方法研究

Low Cycle Fatigue Life Prediction Method Based on Three-Parameter Power Function

关键词:  三参数幂函数  损伤能密度  Masson-Coffin模型  寿命预测  低循环疲劳

Key words:  Three-parameter power function  Damage energy density  Masson-Coffin model  Life prediction  Low cycle fatigue(LCF)

摘要:

为了找到能够更好地预测材料低周疲劳寿命的方法，基于三参数幂函数公式，对引起材料疲劳损伤的原因进行分析，提出了描述损伤能密度与疲劳寿命关系的寿命预测模型。采用高温合金与钛合金等多种材料的低周疲劳试验数据对提出的模型进行分析验证，并将分析结果与传统的Masson-Coffin模型和三参数幂函数公式的分析结果进行对比。结果表明:所提出的损伤能密度模型对不同条件下的材料数据的拟合效果较好，七种不同条件下的材料数据拟合结果中，有六种的相关系数大于0.9，且所有条件下的寿命预测点都在2倍分散带以内，精度高于另两种模型，并且该模型能够确切地描述引起材料低循环疲劳损伤的原因，简洁明了。

Abstract:

To find the more accurate method to forecast materials low cycle fatigue life，the mechanism causing the material fatigue damage were analyzed and a life prediction model that describes the relation between damage energy density and fatigue life was proposed based on the Formula of Three-Parameter Power Function. The low cycle fatigue experimental data of supperalloy and titanium alloy were used to verify the damage energy density model，then，compared its analysis results with the traditional Masson-Coffin model and the Formula of Three-Parameter Power Function’s. The results show that the fitting effect in different conditions of damage energy density model is better than the other two models，in the fitting results of seven conditions，there are six kinds of correlation coefficient being more than 0.9，the damage energy density model has a higher life prediction accuracy and its life forecasting points in seven different conditions are all in the 2 scatter band.In addition，this model is simple and can exactly describe the reason for the low cycle fatigue damage of materials.