Compressive Mechanical Properties of Closed Cell Form Aluminum at Quasi-static and Medium High Strain Rates
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摘要:
结合波形整形技术,根据弹长调试和整形器调试结果改进常规霍普金森压杆试验装置,研究了不同密度（0.48,0.61,0.70 g·cm-3）闭孔泡沫铝准静态（0.001 s-1）与中高应变速率（150 s-1）下的动态压缩力学性能。结果表明：增加弹长可以在获得较大变形的同时实现应变速率的下降,故选用3 m长子弹与4 m长入射杆和透射杆；相比无整形器时,使用直径为20 mm的6层瓦楞纸板整形器后,试样波形持续时间和上升沿时间较长,且在208 μs后就基本达到应力均匀性要求；随着应变速率增加或密度增加,闭孔泡沫铝的压溃应力、屈服强度和平台应力均增大,动静态屈服强度比与相对应变速率成近似幂函数关系,呈现一定的应变速率效应。
Abstract:The conventional Hopkinson pressure bar test device was improved according to the results of missile length adjustment and shaper adjustment combined with waveform shaping technology. The dynamic compressive mechanical properties of closed cell foam aluminum with different densities (0.48,0.61,0.70 g·cm-3) under quasi-static (0.001 s-1) and medium high strain rates (150 s-1) were studied. The results show that increasing the missile length could achieve greater deformation and decrease the strain rate at the same time, so 3 m long bullet and 4 m long incident rod and transmission rod were selected. The waveform duration and rising edge time of the sample after using a 6 layer corrugated board shaper with a diameter of 20 mm were longer compared with those without shaper, and the stress uniformity was basically achieved after 208 μs. With the increase of strain rate or density, the compressive stress, yield strength and platform stress of closed cell foam aluminum increased. The ratio of dynamic yield strength to static yield strength was an approximate power function with the relative strain rate, showing a certain strain rate effect.
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