基于Time-Hardening蠕变模型和“骨点”应力方法预测P92钢缺口圆棒多轴蠕变寿命

PREDICTION OF MULTI-AXIAL CREEP LIFE FOR P92 STEEL NOTCHED BARS BASED ON TIME-HARDENING MODEL AND SKELETAL POINT STRESS METHOD

提出一种用于预测金属缺口圆棒多轴蠕变寿命的方法。基于Time-Hardening蠕变模型,对缺口部位在蠕变过程中的应力分布进行了模拟。将蠕变过程中,缺口最小截面上应力不随时间变化的位置确定为"骨点"。然后借助光滑圆棒试样单轴蠕变试验的寿命-应力关系,使用"骨点"位置的等效应力预测缺口圆棒的多轴蠕变寿命。分别运用该方法和欧盟的多轴蠕变规范方法预测P92钢不同缺口半径的缺口圆棒试样多轴蠕变寿命。结果表明,该方法寿命预测精度与欧盟规范中的方法相当。本方法更加简便,方便工程应用。

A prediction method of multi-axial creep life was proposed for notched bar metal specimen. Based on the Time-Hardening creep model, the stress distribution was simulated in the notched part during creep process. On the minimum section of the notch, the position where stress kept constant during creep process was defined as "skeletal point". According to the relationship between uniaxial tensile creep lives and stresses, the von-Mises equivalent stress of "skeletal point" was used to predict the multi-axial creep life of notched bar. The multi-axial creep lives of different P92 steel notched bars were predicted by this method and European multi-axial creep code respectively. The precision of predicted creep lives of two kinds of method are equal. Furthermore, the proposed prediction method is more simple and convenient for engineering applications.