Plant Biomechanics Group Freiburg, Botanic Garden, Faculty of Biology, University of Freiburg, Freiburg, Germany.
Bioinspir Biomim. 2013 Jun;8(2):025001. doi: 10.1088/1748-3182/8/2/025001. Epub 2013 May 7.
The mechanical properties of artificial foams are mainly determined by the choice of bulk materials and relative density. In natural foams, in contrast, variation to optimize properties is achieved by structural optimization rather than by conscious substitution of bulk materials. Pomelos (Citrus maxima) have a thick foam-like peel which is capable of dissipating considerable amounts of kinetic energy and thus this fruit represents an ideal role model for the development of biomimetic impact damping structures. This paper focuses on the analysis of the biomechanics of the pomelo peel and on its structure-function relationship. It deals with the determination of the onset strain of densification of this foam-like tissue and on how this property is influenced by the arrangement of vascular bundles. It was found here that the vascular bundles branch in a very regular manner-every 16.5% of the radial peel thickness-and that the surrounding peel tissue (pericarp) attains its exceptional thickness mainly by the expansion of existing interconnected cells causing an increasing volume of the intercellular space, rather than by cell division. These findings lead to the discussion of the pomelo peel as an inspiration for fibre-reinforced cast metallic foams with the capacity for excellent energy dissipation.
人工泡沫的机械性能主要取决于基体材料和相对密度的选择。相比之下，在天然泡沫中，通过结构优化而非有意识地替代基体材料来实现性能的优化。柚子（Citrus maxima）的表皮具有厚厚的泡沫状结构，能够消耗大量的动能，因此这种水果是开发仿生冲击阻尼结构的理想模型。本文重点分析了柚子皮的生物力学及其结构-功能关系，探讨了这种泡沫状组织的密实化起始应变及其如何受到维管束排列的影响。研究发现，维管束以非常规则的方式分支——每 16.5%的径向果皮厚度，而周围的果皮组织（中果皮）通过扩展现有相互连接的细胞获得异常的厚度，从而导致细胞间空间的体积增加，而不是通过细胞分裂。这些发现促使我们将柚子皮作为灵感来源，用于纤维增强铸造金属泡沫，以实现优异的能量耗散能力。
