The properties of copper foams with negative Poisson's ratio via resonant ultrasound spectroscopy
The properties of copper foams with negative Poisson's ratio via resonant ultrasound spectroscopy
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DOI：
10.1002/pssb.201384229
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发表时间：
2013-10
期刊：
影响因子：
--
通讯作者：
Dong Li;Liang Dong;R. Lakes
中科院分区：
文献类型：
--
作者：
Dong Li;Liang Dong;R. Lakes
用共振超声光谱（RUS）研究了不同初始相对密度重入Cu泡沫的泊松比。用RUS检测到泡沫中的轻微各向异性，并通过小的单向压缩去除。通过施加一系列永久三轴压缩变形，实现了向可重入泡沫的转变。随着压缩应变的增大，泊松比先减小后增大。在适当的永久压缩应变下，所有初始密度的泊松比最小值约为- 0.7，而在先前通过光学方法确定的相似密度下，泊松比为- 0.6。初始密度较高的泡沫在较低的永久体积压缩时泊松比最小。剪切模量随体积压缩比的增大而增大，在泊松比最小值点附近出现一个小驼峰。
The Poisson's ratios of re‐entrant Cu foams with different initial relative densities were studied by resonant ultrasound spectroscopy (RUS). Slight anisotropy in foam was detected by RUS and removed by a small unidirectional compression. The transformation into the re‐entrant foam was accomplished by applying a sequence of permanent triaxial compression deformations. The Poisson's ratio first decreases and then increases with increasing compression strain. A minimum in Poisson's ratio of approximately −0.7 for all initial densities was achieved with an appropriate permanent compression strain, compared with −0.6 at similar density determined earlier via optical methods. Foams with higher values of initial density attained minima in Poisson's ratio at lower permanent volumetric compression. The shear modulus increased with increasing volumetric compression ratio, and showed a small hump near the point corresponding to Poisson's ratio minimum.