试论镁铝合金高应变率单轴压缩拟合本构关系的代入校核

从实验与数值模拟的结合上,确定与考察了镁铝合金在一维应力高应变率压缩状态下的本构关系。把由一维准静态及动态压缩试验结果所拟合的经验性本构关系代入镁铝合金的SHPB试验的全过程数值模拟,可再现实验测得的反射波波形及透射波波形。数值模拟也表明,采用SHPB试验经典分析所估算的应力、应变、应变率与试件典型微元在试验过程中所经受的应力应变、应变率也基本一致,然而,应变率并非常值。

ON THE CHECKING OF FITTED CONSTITUTIVE RELATION OF AN MG-AL ALLOY UNDER UNIAXIAL COMPRESSION AT HIGH STRAIN RATES

The constitutive relation of an Mg-Al Alloy under uniaxial compression at high strain rates is fitted and checked using the SHPB(Split Hopkinson Pressure Bar)experimental results and the numerical simulation based on the fitted constitutive law of the specimen.Using the constitutive relation of the Mg-Al Alloy determined by quasi-static and dynamic compression tests in the one-dimensional simulation of the SHPB test,the reflected and transmitted pulses of SHPB tests can be reproduced.Furthermore,the stress,strain and strain rate of the Mg-Al Alloy obtained in the SHPB test are consistent with those estimated by the classical SHPB analyses.However,it should be noted that the strain rate of the specimen is not constant during SHPB test.