A nondestructive impulse excitation technique was used to investigate Poisson’s ratio of powder metallurgical pure closed-cell aluminium foams according to ASTM E 1876 within the foam density range of 0.430–1.390 g·cm−3. Instead of a constant value of 0.34, as according to Gibson and Ashby’s assumption for the Poisson’s ratio of metallic foams, the decrease of the Poisson’s ratio with decreasing foam density was observed. Observed Poisson’s ratio data were in the range of 0.21–0.34. To check the validity of the results, the Young’s modulus was calculated using Poisson’s ratio and its dependence on relative density was successfully modelled using the usual power law function with characteristic exponent of 1.72 ± 0.1. This confirms that the obtained experimental results for Poisson’s ratio are valid. Finally, rule of mixture and percolation theory were used to model the observed decrease of Poisson’s ratio with increasing porosity.
展开▼
机译：根据ASTM E 1876，采用无损脉冲激励技术研究粉末冶金纯闭孔铝泡沫的泊松比，其泡沫密度在0.430–1.390 g·cm −3 范围内。吉布森（Gibson）和阿什比（Ashby）对金属泡沫的泊松比的假设不是0.34的恒定值，而是观察到随着泡沫密度降低，泊松比的降低。观察到的泊松比数据在0.21-0.34之间。为了检验结果的有效性，使用泊松比计算了杨氏模量，并使用特征指数为1.72±0.1的常用幂定律函数成功地模拟了其对相对密度的依赖性。这证实了所获得的泊松比实验结果是有效的。最后，使用混合法则和渗流理论对所观察到的泊松比随孔隙率增加而降低的情况进行建模。
展开▼
