一种基于归一化参数的蠕变模型

A creep model based on normalized parameters

针对传统蠕变模型(如Norton律)不能模拟蠕变第3阶段的不足,提出了一种基于归一化参数的蠕变模型,该模型以归一化时间为变量,以归一化应力和归一化温度为参数,可完整描述蠕变曲线的所有3个阶段.在该模型的基础上提出了能更好地描述蠕变曲线第1阶段的改进形式.利用所发展的模型对直接时效GH4169G材料的蠕变试验曲线3个阶段进行了较好地模拟,验证了该模型的描述蠕变变形的能力;同时确立了所发展模型中各参数与归一化温度和归一化应力之间的函数关系,取得了较好的效果;并且能与有限元软件结合,表明所发展的模型可应用于实际结构的蠕变分析.

In view of the deficiency that the traditional creep models, e.g. the Norton＇s law, cannot be used to simulate the third stage of creep, a creep model based on normalized time as a variable and the normalized stress and normalized temperature as parameters was presented. The developed model could describe all three stages of the creep curves. On the basis o{ the developed model, an improved model was put forward to describe the first stage of the creep curves better. Then feasibility of the developed model was validated by use of the experimental data of the direct aged GH4169G. The relationship between the parameters of the developed model and the dimensionless temperature, dimensionless stress was established. And the models can be used in finite element software, showing that the model can be applied to simulate the creep behavior of realistic structure.