In-situ deformation of an open-cell flexible polyurethane foam characterised by 3D computed microtomography
In-situ deformation of an open-cell flexible polyurethane foam characterised by 3D computed microtomography
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DOI：
10.1023/a:1014920902712
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发表时间：
2002-04-15
影响因子：
4.5
通讯作者：
Baruchel, J
中科院分区：
文献类型：
--
作者：
Elliott, JA;Windle, AH;Baruchel, J
使用法国格勒诺布尔 ESRF 的 ID19 光束线上的 X 射线显微断层扫描技术观察开孔软质聚氨酯泡沫的变形行为。断层扫描由 1024 个立方体素组成，是在 0 至 80% 的压缩应变范围内从泡沫中心附近的小区域收集的体素大小为 6.6 μm。结果表明，压缩的初始阶段由倾斜于压缩方向的支柱中的少量弹性弯曲所占据。在 23% 应变下，在结构中观察到完全塌陷的带。到 63% 应变时，有证据表明支柱相互碰撞，这与致密化状态相对应。不规则泡沫（即具有支柱长度和泡孔尺寸分布的泡沫）的压缩似乎涉及模量的突然变化，并伴随着密度的局部增加。如果无法在真实的原位加载条件下进行连续显微断层成像，那么这种性质的观察结果将很难明确地解释。有限元分析 (FEA) 过程首先通过数学骨架化过程根据实验数据构建节点支柱模型。这些用于导出节点协调、支柱长度和单元尺寸分布。然而，由于实验确定的泡沫结构缺乏周期性，因此无法将弹性特性与有限元分析进行直接比较。 (C) 2002 年 Kluwer 学术出版社。
The deformation behaviour of an open-cell flexible polyurethane foam was observed using X-ray microtomography on the ID19 beamline at the ESRF in Grenoble, France. Tomographs, consisting of 1024 voxels cubed, were collected with a voxel size of 6.6 mum from a small region near the centre of the foam at a range of compressive strains between 0 and 80%. The results show that the initial stages of compression are taken up by small amounts of elastic bending in struts that are inclined to the compression direction. At 23% strain, entirely collapsed bands were observed in the structure. By 63% strain, there was evidence of struts impinging on each other, corresponding to the densification regime. The compression of an irregular foam (i.e. one with strut length and cell size distributions) appears to involve a sudden change in modulus, accompanied by localised increases in density. Observations of this nature would have been extremely difficult to interpret unambiguously without the ability to carry out sequential microtomographic imaging under realistic in situ loading conditions. The process of finite element analysis (FEA) was begun by constructing node-strut models from the experimental data by a mathematical skeletonisation process. These were used to derive node coordination, strut-length and cell-size distributions. However, direct comparison of the elastic properties with FEA was hampered by the absence of periodicity in the experimentally determined foam structures. (C) 2002 Kluwer Academic Publishers.