HRB335钢多轴疲劳寿命预测的改进临界面模型

Improved Critical Plane Model for Multiaxial Fatigue Life Prediction of HRB335 Steel

对HRB335钢进行单轴(拉压、纯扭路径)和多轴非比例(圆形、菱形和蝶形路径)加载疲劳试验,在试验基础上标定等效应变法、KBM临界面模型和引入拉伸因子的临界面模型(拉伸因子模型)参数,对比分析了各模型对HRB335钢多轴疲劳寿命预测的有效性;通过引入路径非比例度和材料附加强化参数对拉伸因子进行修正,并对修正拉伸因子模型的预测结果进行了验证。结果表明:等效应变法对HRB335钢疲劳寿命的预测结果大部分超出三倍误差范围,KBM临界面模型与拉伸因子模型对圆形和蝶形路径加载下的疲劳寿命预测结果也部分超出了三倍误差范围;修正拉伸因子模型对5种加载路径下HRB335钢的疲劳寿命预测结果都位于三倍误差范围内,并且对Q235钢和304不锈钢的多轴疲劳寿命预测值也与实测结果吻合,该模型合理有效。

Uniaxial(tension-compression and torsion paths)and nonproportional multiaxial(circular,rhombic and butterfly paths)loading fatigue tests were carried out on HRB335 steel.On the basis of the tests,the parameters of equivalent strain method,KBM critical plane model and critical plane model with stretching factor(stretching factor model)were calibrated,and the effectiveness of each model for multiaxial fatigue life prediction of HRB335 steel was compared and analyzed.The stretching factor was improved by introducing path nonproportionality and a material additional strengthening parameter,and the prediction of the improved stretching factor model was verified.The results show that the fatigue life prediction of HRB335 steel by the equivalent strain method was mostly out of the triple error range.The fatigue life prediction by the KBM critical plane model and stretching factor model under circular and butterfly path loading partly exceeded the triple error range.The fatigue life prediction of HRB335 steel under five loading paths by the improved stretching factor model was all in the triple error range,and the multiaxial fatigue life prediction of Q235 steel and 304 stainless steel was also consistent with the test results,indicating the model was reasonable and effective.