基于相对即时密度的泡沫铝材料力学性能研究

An Experimental Study On the Mechanic Behaviors of Aluminum Foam Based on the Relative Current Density

通过对圆柱形泡沫铝试件进行静态压缩和冲击实验,考察了泡沫铝的初始密度、孔径和尺寸等因素对材料应力应变关系的影响,研究了基于相对即时密度的泡沫铝材料的塑性行为。实验所用泡沫铝试件包含四种尺寸,三种孔径及多种初始密度。实验结果表明,初始密度对泡沫铝的应力应变关系有着显著的影响,而其他因素,如孔径、试件尺寸等的影响较小。基于实验结果,提出了一种新的泡沫铝材料力学性能的描述方法,即用材料的相对即时密度与应力的关系来描述泡沫铝材料的塑性行为。该关系适用于静态和动态加载情况,只是两种情况下的参数不同。基于该方法,发现泡沫铝的塑性行为可以用单一的应力—相对即时密度关系描述,这一关系甚至不依赖于材料的初始密度,这将使泡沫铝材料塑性行为的描述大大简化。

By the static and impact experiments for aluminum foam cylindrical specimens were performed, and the effects of initial density, aperture and geometry on the relation of stress and strain were analyzed. Then the plastic behavior of aluminum foam was studied based on the relative current density. The specimens with four kinds of geometry dimension, three kinds of average cell diameter and various initial densities were considered in the tests. The results show that the initial density has significant effect on the relation of stress and strain, but other factors such as aperture and geometry have little effect on it. According to the results obtained, a new kind of description of the aluminum foam′s mechanic character of the plasticity is suggested, that is the relation between stress and relative current density of aluminum foam instead of the relation between stress and strain. This new relation is applicable to both static and impact loading conditions; only different parameter′s values should be inserted for the two cases. By the means, it is found that the plastic behavior of aluminum foam can be depicted uniquely by the relation between stress and relative current density, which is even not affected by the initial density of aluminum foam. Thus, the plastic description of aluminum foam would be simplified greatly.