蛛丝β-片状纳米晶体启发的蜂窝结构动态力学特性研究

Dynamic behavior of spiderβ-sheet nanocrystalline inspired honeycomb structures

蜘蛛曳丝具有优异的力学特性,其β-片状纳米蛋白晶体在微观尺度下发挥着重要作用;受β-片状纳米蛋白晶体规则的拓扑结构启发,抽象出一种含凹角和六边形特征的新型蜂窝结构。通过数值模拟及理论分析发现,该结构具有丰富且独特的变形模式。凹角旋转闭合和斜边弯曲的变形机制使其在高速冲击下具有零泊松比性质;低速冲击下,该结构为均匀的胞元整体旋转变形,且由于变形中形成了新的胞体结构,平台应力阶段存在明显分段现象;进一步地,给出了该结构的变形模式图和平台应力公式;针对旋转变形机制多胞体蜂窝结构在低速冲击下平台应力分段的特征,提出了修正后的平台应力表达式。经对比分析,发现该结构与六边形蜂窝结构的吸能能力处于同一水平,可以为对横向变形有要求的场合提供防护选择。

The major ampullate silk possess excellent mechanical properties and itsβ-sheet nanocrystalline plays a crucial role in micro-scale.Inspired by its structure,a new type of honeycomb topology was abstracted.Through simulation and theoretical analysis,it was found that theβ-sheet nanocrystalline inspired honeycomb has abundant and unique deformation modes.At high impact velocity,this new honeycomb has zero Poisson’s ratio due to re-entrant angel’s inward depression and hypotenuse’s bend.At low impact velocity,the deformation mechanism is cell’s overall rotation and tensile deformation.Because of this deformation mechanism,there are two plateau stress periods in response curve.Furthermore,the deformation mode map of the structure was given,and the plateau stress formula was obtained.According to the stress characteristics,the plateau stress formula of cellular honeycomb structure under rotating deformation mechanism was proposed.The energy absorption capacity of this honeycomb is approximate to hexagonal honeycomb.It can provide a choice for protection occasions against transverse deformation.