5083H111铝合金宽应变率拉伸动态本构模型

结合5083H111铝合金较宽应变率范围2×10-4 ~ 4×102s-1内的拉伸实验数据，揭示该铝合金的拉伸“V”型率效应特征，分析对数应变率敏感系数λ和切线模量Et的应变率和应变相关性，进而通过对Johnson-Cook模型的修正来建立合理描述5083H111铝合金较宽应变率范围内的动态拉伸本构模型。建立的动态本构模型中，流动应力包括应变率相关和应变相关两部分。该模型合理描述了5083H111铝合金的拉伸“V”型率效应特征，预测结果与实验结果较为一致。另外，结合破坏应变的对数应变率敏感系数β，得到了拉伸破坏应变预测方程，其预测结果也与实验结果基本一致。

TENSILE DYNAMIC CONSTITUTIVE MODEL OF 5083H111 ALUMINUM ALLOY AT A WIDE RANGE OF STRAIN RATES

Combined with tensile experimental data of 5083H111 aluminum alloy at a wide range of strain rates from 2×10-4 to 4×102s-1, the V-typed strain-rate effect of this aluminum alloy is analyzed. The strain-rate and strain dependence of the logarithmic strain rate sensitivity coefficient λ and tangent modulus Et are discussed. Then, a dynamic constitutive model is established to describe the dynamic tensile behavior of 5083H111 aluminum alloy at a range of lower and middle strain-rates by modifying the Johnson-Cook model. The model reflects the V-typed strain-rate effect of tensile deformation of the aluminum alloy at researching strain-rates, and the predicted results of the proposed model are in good agreement with the experimental ones. Furthermore, based on the logarithmic strain-rate sensitivity coefficient β of failure strain, a new equation to predict the tensile failure strain of the alloy is formulated, and the predicted results are basically consistent with the experimental ones.