铝合金材料蠕变模型参数优化反演方法

摘要

In order to estimate parameters of creep models of aluminum alloy materials,a parameter inver-sion procedure is proposed with optimization algorithm,which is based on uniaxial tension creep experi-ments for aluminum alloy materials.For three kinds of aluminum alloy materials,the parameters of creep models both for Norton-Bailey and Prandtl-Garofalo creep model are determined.The investigation shows that the time exponent (γ+1) in creep model changes from 0.2 to 0.4,and the equivalent stress expo-nent (β) in creep model changes from 6.0 to 7.6.For 7050 and 7B04 aluminum alloy materials,Prandtl-Garofalo creep model shows higher forecasting precision.For 7075 aluminum alloy material,Norton-Bai-ley creep model shows higher forecasting precision.The forecasting creep strains based on estimated pa-rameters of creep models agree well with observed ones.The effectiveness of proposed parameter estima-ting procedure of creep models of aluminum alloy materials is validated from experimental data.%基于铝合金材料单轴拉伸蠕变实验观测数据，提出了铝合金材料蠕变模型参数优化反演方法。针对3种典型的铝合金材料，分别反演确定了Norton-Bailey和Prandtl-Garofalo蠕变模型中的参数。计算结果表明，蠕变应变与时间的（0．2～0．4）次幂成正比，与等效应力的（6．0～7．6）次幂成正比。对于7050和7 B04铝合金材料， Prandtl-Garofalo蠕变模型给出了较高的预测精度。对于7075铝合金材料，Norton-Bailey蠕变模型给出了较高的预测精度。铝合金材料蠕变模型预测的应变与实验值基本一致，验证了所提出模型参数反演方法的有效性。