闭孔铝泡沫在静压痕下的力学响应

Mechanical response of a closed-cell Al foam under static indentation

采用球形压头对闭孔铝泡沫材料进行了准静态压痕实验,研究了不同直径、铝泡沫相对密度及边界条件对铝泡沫的压痕硬度、吸能能力及能量吸收率的影响。研究表明,铝泡沫在球形压头作用下的响应曲线可采用幂函数形式进行描述,幂函数指数随相对密度的增大而线性增加。铝泡沫压痕处的断面显示铝泡沫变形被严格限制在压头之下,铝泡沫的压痕变形是局部的不均匀变形。铝泡沫的压痕硬度及吸能能力均随压头直径的增大而线性减小,但它们却均随铝泡沫相对密度的增大而线性增大;能量吸收率不随压头直径和铝泡沫相对密度而变化。在一定压痕深度范围内,刚性基础和简支条件对铝泡沫的压痕响应影响可以忽略不计。最后基于实验数据分别建立了压痕硬度和吸能能力与压头直径及铝泡沫相对密度的关系。

The quasi-static indentation tests of the closed-cell aluminum foam under the spherical-end cylindrical indenters were performed.The effects of indenter size,relative density and boundary condition on the indentation hardness,energy absorbing capability and energy absorbing efficiency of aluminum foam were investigated.The results show that the power function can be used to describe the indentation response curves of Al foam under the spherical-end cylindrical indenters and the index of power function linearly increases with the increasing of indenter size.Cross-sectional views of the indented specimens show that the deformation is confined to the region under the indenter with very little transverse spread,and the indentation deformation of aluminum foam is non-uniform.The indentation hardness linearly decreases with the increasing of indenter sizes,but it linearly increases with the increasing of relative density.The energy absorbing efficiency of aluminum foam is not related to the indenter size and relative density.In a certain indentation depth range,the difference between rigid foundation and simply supported conditions on the indentation response of Al foam can be ignored.Finally,the relations between the indentation hardness,energy absorption capacity,the indenter size and relative density are established by fitting the experimental data.