Microstructural characterisation and experimental determination of a multiaxial yield surface for open-cell aluminium foams
Microstructural characterisation and experimental determination of a multiaxial yield surface for open-cell aluminium foams
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DOI：
10.1016/j.matdes.2017.06.017
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发表时间：
2017-10-05
影响因子：
8.4
通讯作者：
Diebels, S.
中科院分区：
文献类型：
--
作者：
Jung, A.;Diebels, S.
泡沫金属是一种具有生物启发性的微观非均质材料，具有很强的结构-性能关系。它们的整体力学性能强烈地依赖于支柱的局部微观力学性能和泡沫的孔几何形状。为了能够设计由泡沫制成的部件，对泡沫在实际复杂应力状态下的屈服行为的坚实的微观力学和宏观力学理解是必不可少的。然而，到目前为止，泡沫材料的实验屈服面数据是非常有限的。本贡献涉及的结构表征的开孔泡沫铝的不同孔径的X射线计算机断层扫描（CT）。根据CT数据评价支柱几何形状，例如横截面形状和沿支柱沿着的质量分布。通过单轴拉伸、压缩、纯扭、压扭复合和拉扭复合试验，对10、20和30 ℃泡沫材料的屈服面进行了实验研究。这导致在开孔泡沫铝的文献中报道的最全面的实验数据集之一。屈服面的形状及其不对称程度与结构表征的几何数据有关。它提供了一个更深入的了解泡沫铝在复杂的多轴应力状态。
Metal foams are bio-inspired microheterogeneous materials, which exhibit a strong structure-property relationship. Their global mechanical properties depend strongly on the local micromechanical properties of the struts and on the pore geometry of the foams. A solid micromechanical and macromechanical understanding of the yield behaviour of the foams under realistic complex stress states is essential in order to be able to design components made of foams. However, up to now, experimental yield surface data for foams are very limited.The present contribution deals with the structural characterisation of open-cell aluminium foams of different pore sizes by X-ray computed tomography (CT). The strut geometry e.g. regarding cross-sectional shape and the mass distribution along the struts is evaluated from the CT data. Yield surfaces for 10, 20 and 30ppi foams are experimentally probed by performing uniaxial tensile and compression tests, pure torsion as well as combined compression-torsion and tension-torsion tests. This results in one of the most comprehensive experimental data sets in the literature ever reported for open-cell aluminium foams. The shape of the yield surface and its degree of asymmetry were connected to the geometric data from the structural characterisation. It provides a deeper understanding of aluminium foams under complex multiaxial stress states.