Image-based correlation between the meso-scale structure and deformation of closed-cell foam

MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING

卷:688

Article

Sun, Yongle¹  Zhang, Xun²  Shao, Zhushan³  Li, Q. M.^1,4 

[1] Univ Manchester, Sch Mech Aerosp & Civil Engn, Sackville St, Manchester M13 9PL, Lancs, England

[2] Univ Manchester, Sch Mat, Henry Moseley Xray Imaging Facil, Upper Brook St, Manchester M13 9PL, Lancs, England

[3] Xian Univ Architecture & Technol, Sch Civil Engn, Xian 710055, Peoples R China

[4] Beijing Inst Technol, State Key Lab Explos Sci & Technol, Beijing 100081, Peoples R China

关键词: Aluminium foam;    Cell structure;    Crushing;    Computed tomography;    Image-based modelling;   

DOI  :  10.1016/j.msea.2017.01.092

来源: Elsevier

【 摘 要 】

In the correlation between structural parameters and compressive behaviour of cellular materials, previous studies have mostly focused on averaged structural parameters and bulk material properties for different samples. This study focuses on the meso-scale correlation between structure and deformation in a 2D foam sample generated from a computed tomography slice of Alporas(TM) foam, for which quasi-static compression was simulated using 2D image-based finite element modelling. First, a comprehensive meso-scale structural characterisation of the 2D foam was carried out to determine the size, aspect ratio, orientation and anisotropy of individual cells, as well as the length, straightness, inclination and thickness of individual cell walls. Measurements were then conducted to obtain the axial distributions of local structural parameters averaged laterally to compression axis. Second, the meso-scale deformation was characterised by cell-wall strain, cell area ratio, digital image correlation strain and local compressive engineering strain. According to the results, the through-width sub-regions over an axial length between the average (lower bound) and the maximum (upper bound) of cell size should be used to characterise the meso-scale heterogeneity of the cell structure and deformation. It was found that the first crush band forms in a sub-region where the ratio of cell-wall thickness to cell-wall length is a minimum, in which the collapse deformation is dominated by the plastic bending and buckling of cell walls. Other morphological parameters have secondary effect on the initiation of crush band in the 2D foam. The finding of this study suggests that the measurement of local structural properties is crucial for the identification of the weakest region which determines the initiation of collapse and hence the corresponding collapse load of a heterogeneous cellular material.

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