数字图像相关方法在闭孔泡沫铝压缩试验中的应用

Compressive Test of Closed-cell Aluminum Foam Based on Digital Image Correlation Method

为了了解相对密度与胞孔结构对闭孔泡沫铝力学性能的影响,本文采用放大成像及数字图像相关技术对两种不同密度的泡沫纯铝试样进行了实验研究。利用数字图像相关方法对泡沫纯铝变形前后的图像进行相关计算,获得了弹性范围内静态压缩情况下闭孔泡沫铝材料表面的全场变形及局部孔结构的变形,同时根据试验结果计算了试件的名义弹性模量。实验结果表明泡沫铝整体孔结构的变形与泡沫金属材料相对密度有关,而单个孔结构的变形主要与孔壁面光滑程度和皱褶有关。实验结果还表明图像相关方法能够有效地应用于闭孔泡沫金属的力学性测量和评估的研究。

This paper primarily concerns the role of relative densities and cellular structures in influencing on the mechanical behaviour of closed-cell aluminum foams. Two closed-cell pure aluminum foams have been investigated by use. of optical observation at large magnification. Based on calculating correlation of the images captured before and after deformation, digital image correlation method （DICM） was employed to measure the displacement of closed-cell aluminum foam materials under uniaxial compression. The whole-field deformation and displacement distribution of cells are presented in this paper, and the nominal Young＇s modulus of the tested specimen is also obtained. Experimental results show that the static mechanical properties of closed-cell aluminum foam is depended on the relative density, and the cell deformation is related to its shape and change with its wavy wall..Experimental results also indicate that DICM is an effective approach to investigate and evaluated the mechanical behavior of closed-cell aluminum foam materials.