基于塑性应变能的多轴低周疲劳寿命预测模型

在分析多轴疲劳损伤机理的基础上,提出一个新的多轴低周疲劳寿命预测模型。此模型以临界平面上的塑性应变能作为疲劳损伤参量,分析了临界平面的特点并给出了损伤参量的计算过程。利用该模型预测了不同加载路径下的304不锈钢试件的疲劳寿命,并与试验值进行比较。结果表明,该损伤参量具有明确的物理意义,能够适用于多轴比例与非比例等各种复杂的加载情况。

MULTIAXIAL LOW CYCLE FATIGUE LIFE PREDICTION MODEL BASED ON PLASTIC ENERGY

The mechanism of the multiaxial fatigue damage is analyzed and a new plastic energy-based approach for predicting multiaxial fatigue life is described. In the approach the fatigue damage parameter is defined as the plastic energy on the critical plane. Features of the critical plane are discussed and the calculation of the damage parameter is presented. Verification of the model is achieved by comparing the predictions obtained by using the new model with the experimental data of 304 stainless steel under different loading conditions. The results show that the fatigue damage parameter has definite physical meaning and the approach can be used under either proportional loading or nonproportional loading.