闭孔泡沫铝的塑性泊松比

在表征闭孔泡沫铝的力学性能中，塑性泊松比是较为重要的参数之一。本文应用Kelvin十四面体模型构建出不同相对密度的闭孔泡沫铝三维细观模型并采用LS-DYNA对所得细观模型进行单轴准静态压缩计算。数值模拟分析发现，随着轴向应变的增加，泡沫铝泊松比-轴向应变曲线呈倒S形，存在峰值和极小值，曲线变化规律与泡沫铝胞孔的变形有密切关系。根据泊松比-轴向应变曲线与胞孔变形之间的关系，给出了平均塑性泊松比的定义。计算结果显示，随着相对密度的提高，闭孔泡沫铝的平均塑性泊松比增大。当闭孔泡沫铝的相对密度低于0.1时，其平均塑性泊松比接近于零，计算中可以忽略；当闭孔泡沫铝相对密 度大于0.1时，其平均塑性泊松比随相对密度的增加而呈线性从0.17增加到0.5

Plastic Poisson's ratio of closed-cell aluminum foams

Of all the parameters that characterizing CCAF(closed-cell aluminum foam) mechanical properties, the plastic Poisson's ratio is a important one. In this study, based on Kelvin model, the three-dimensional mesoscopic models of CCAFs are established. The plastic Poisson's ratio of different relative densities three-dimensional mesoscopic models of CCAFs under uniaxial quasi-static compression is numerical analyzed. The calculation results show that Poisson's ratio of CCAF changes like a inverse S shape with the increase of axial strain. The average plastic Poisson's ratio of CCAF has a close relationship with its relative density. When the relative density is less than 0.1, the average plastic Poisson's ratio can be ignored; when the relative density is bigger than 0.1, the average plastic Poisson's ratio shows a linear increase with the enhancement of the relative density and grows from 0.17 to 0.5.