中文摘要：

通过扫描电子显微镜和光学显微镜研究了2种天然高分子泡沫材料，即玉米秆芯和高粱秆芯切面的泡孔形态结构及胞体堆砌模式。测试了材料在轴向和径向的压缩杨氏模量和压缩屈服强度等力学性能，探讨了泡沫材料的压缩变形机制，建立了天然泡沫材料的复合结构模型，并分析了力学性能与复合结构的关系。研究结果表明，这2种天然泡沫均由一种近似六棱柱和少量圆形管状胞体构成，它们在轴向的杨氏模量和屈服强度分别比径向的大4倍以上。导管增强的复合结构是引起天然泡沫材料具有明显各向异性的重要原因，其中厚壁导管的轴向杨氏模量约为不规则六棱柱胞体的105倍。

英文摘要：

The compressive yield stress and modulus of the two natural foam cores of kaoliang stem and corn stem were tested. Their structures and morphologies were determined by scanning electron microscope. The different compressive deformation mechanics of the foams were discussed. A compound structure model made up of hexangular prisms and tubular cells was established from the observation on scanning electron microscope photographs. The effects of the compound structure of the foams on their mechanical properties were studied on the basis of the model. The results show that the compressive yield stress and modulus of the two natural foam cores in the axial direction are more than 4 times of those in the radial direction. The compound structure of the foams reinforced by the tubular cells has more significant effects on the corresponding mechanical properties of the foams. The axial compressive modulus of a tubular cell is 105 times that of an abnormal hexangular prism cell.