各向异性弹性开孔泡沫压缩行为的数值模拟

基于各向异性开孔泡沫的随机模型,对低密度弹性开孔泡沫材料的压缩力学行为进行了有限元数值模拟,得到了其应力-应变曲线及弹性坍塌强度.讨论了模型的随机度、各向异性比及相对密度对力学性能的影响.结果表明,沿不同方向加载时,各向异性胞体的微观变形机制不尽相同,且变形较大时,支柱的弹性屈曲占主导地位;模型随机度的增大,使两个方向的压缩无量纲应力-应变曲线均有所降低,且 λ =1时的无量纲应力-应变曲线与实验曲线吻合得较好.此外,开孔泡沫各向异性比的增大可使胞体伸长方向的弹性坍塌强度增大,而垂直方向的弹性坍塌强度则减小.

Numerical modeling of high strain compression of anisotropic elastic open-cell foams

Based on the anisotropic irregular model, the compressive mechanical properties of low-density open-cell elastic foams were simulated by finite element analysis. The compressive stress-strain curves and elastic collapse strength were obtained in order to investigate the influence of anisotropic ratio, random degrees and relative densities on the mechanical properties. The results show that the deformation mechanism is different when loads are applied in different directions, and strut buckling becomes the main deformation mechanism at large compressive strains. A larger anisotropic ratio leads to larger elastic collapse strength along the cell rising direction and lower elastic collapse strength in the vertical direction. Meanwhile, the higher random degree causes lower stress-strain curves in both directions. When λ =1, the effective stress-strain curves well accord with the experimental curves.