采用改进的SHPB方法对泡沫铝动态力学性能的研究

An Improved SHPB Method and Its Application in the Study of Dynamic Mechanical Behavior of Aluminum Foams

本文改进了传统的分离式霍布金森压杆(SHPB)技术,采用夹在透射杆中的PVDF压电计直接测量透射杆中的应力时程.同时,采用输入波形整形技术,通过调整加载波形,使试样加载过程中保证均匀变形及应力平衡.利用此改进了的SHPB技术对泡沫铝进行了高应变率下的动态压缩实验.实验结果表明:泡沫铝的动态应力应变曲线具有泡沫材料的应力应变曲线的"三阶段"特征(elasticregion,collapseregionanddensificationregion),并且应变率对其力学性能影响明显.

The conventional SHPB technique is improved by using PVDF gauges embedded in the transmission bar to measure the weakly transmitted stress profile directly. Uniform deformation and dynamic stress equilibrium in the specimen are guaranteed by means of incident pulse shaping technique during the dynamic loading. This improved SHPB method was applied to determine the compressive dynamic mechanical response of aluminum foams at high strain rate. Experiment results show that the compressive stressstrain curves of Alfoams also have the 'three regions' character appeared in general foam materials′, namely elastic region, collapse region and densification region. The ratedependence of the dynamic mechanical behavior of aluminum foams is also shown.