Microstructural characterization and constitutive modeling of deformation of closed-cell foams based on in situ x-ray tomography
| Autor: | Z.L. Xie, Honglan Xie, Xianghui Xiao, Sheng-Nian Luo, J.Y. Huang, H.W. Chai |
|---|---|
| Rok vydání: | 2020 |
| Předmět: |
010302 applied physics
Specific modulus Materials science Mechanical Engineering 02 engineering and technology 021001 nanoscience & nanotechnology Compression (physics) Microstructure 01 natural sciences Finite element method Buckling Mechanics of Materials 0103 physical sciences General Materials Science Deformation bands Tomography Composite material Deformation (engineering) 0210 nano-technology |
| Zdroj: | International Journal of Plasticity. 131:102730 |
| ISSN: | 0749-6419 |
| Popis: | Polymethacrylimide (PMI) foams own the highest specific stiffness and strength of all foams. In situ x-ray micro computed tomography (CT) is used to map three-dimensional (3D) microstructures of this representative closed-cell foam under quasi-static compression. The strain fields obtained via digital volume correlation reveal divergent types (discrete or spreading) of deformation banding for the PMI foam with different densities (52 or 75 kg m−3). Significant cell collapse occurs in the deformation bands, leading to ∼ 40% reduction of the mean cell size, and alignment of cell orientations. Microstructure-based finite element analysis confirms that elastic buckling of cell walls dominates cell collapse, and the buckling strength of walls depends highly on their thicknesses and inclination angles. An edge segmentation technique is then used to quantify the morphology and buckling strength index of cell walls. The spatial distribution of the weakest 3% cell walls correlates well with the modes of deformation banding. Based on elastic buckling of cell walls, new analytical models are developed to predict the strength–density scaling law and stress–strain curves of the PMI foam, which agree well with the experimental results. |
| Databáze: | OpenAIRE |
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