复合应力下泡沫铝屈服行为实验研究

 采用ARCAN双轴加载装置和材料实验机（INSTRON 5544），对相对密度为8.5%的闭孔泡沫铝（Alporas）进行了不同应变率下的双轴加载实验。在宏观等效应变率为7.0×10^-3~1.0×10^-1 s^-1范围内测得实验屈服面，并与泡沫金属的3种屈服准则进行了比较。比较结果表明：在主应力空间下，实验屈服面与Miller和Deshpande-Fleck屈服准则吻合较好，Gibson屈服准则过小估计了测试泡沫铝的实验屈服面；被测泡沫铝的实验屈服面在宏观等效应变率7.0×10^-3~1.0×10^-1 s^-1范围内对应变率不敏感。

Experimental Investigation on the Yield Behavior of Aluminum Foams under Combined Stress States

The initial yield behavior of Alporas closed-cell aluminium foams with relative density 8.5% under biaxial loading has been experimentally investigated using the Arcan apparatus and the universal testing machine(INSTRON 5544).The experimental yield surfaces measured from biaxial experiments are compared with various proposed phenomenological yield surface models.The comparison result indicates that the experimental data are consistent with both Miller and Deshpande and Fleck criteria.Biaxial experiments have been carried out on aluminium foams at various loading velocities to study the effect of strain rate on the initial yield surface.The results showed that the initial yield stresses of Alporas closed-cell aluminium foams are not sensitive to the equivalent strain rate ranged from 7.0×10-3 s-1 to 1.0×10-1 s-1.