小冲杆法确定蠕变Norton参数

Determination of Norton Creep Parameters by Small Punch Creep Test

基于Chakrabarty薄膜伸张模型,推导出小冲杆蠕变的等效应变和应力表达式,将小冲杆蠕变试验得到的试样中心挠度-时间曲线化为试样中心蠕变应变-时间曲线,载荷转化为等效应力,通过非线性拟合应力、最小蠕变速率得到P91材料小冲杆试验的Norton蠕变参数。建立P91小冲杆蠕变的有限元模型并进行大量模拟,对蠕变第2阶段的试验结果和模拟结果进行对比分析,提出反向有限元的方法。结果表明:小冲杆蠕变试验能够得到材料蠕变参数,和单轴蠕变试验结果对比发现,采用反向有限元的方法比小冲杆蠕变试验能更加方便、快捷、准确地得到P91蠕变参数。

Based on the Chakrabarty＇s stretch membrane model, the relationship between the creep strain and the deflection was derived to calculate the experimental data from small punch creep test（SPC）, and the relationship between the creep stress and the load was derived too. The Norton creep parameters of Pgl material can be obtained from the experiments with nonlinear fitting. Then employed a finite element model of small punch creep test, a new method called inverse finite element was derived from comparison the second stage of experiments and simulations. The results show that the creep parameters of material can be obtained by small punch test. Based on tensile creep results, it is more convenient and accurately to get the creep parameters of P91 material by inverse finite element method.