Roughness-dependent friction force of the tarsal claw system in the beetle Pachnoda marginata (Coleoptera, Scarabaeidae).
Roughness-dependent friction force of the tarsal claw system in the beetle Pachnoda marginata (Coleoptera, Scarabaeidae).
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发表时间：
2002-08
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通讯作者：
Z. Dai;S. Gorb;U. Schwarz
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作者：
Z. Dai;S. Gorb;U. Schwarz
本文研究了边缘厚壳甲虫（Pachnoda marginata，鞘翅目，金龟子总科）自由行走时爪所产生的抗滑力，着重研究了爪尖尺寸与基底质地的关系。为了评估爪可以与基板相互作用的力范围，使用测力传感器测量由自由移动的腿产生的力。为了获得有关爪的材料特性的信息，在断裂实验中测试其机械强度，并通过扫描电子显微镜研究断裂爪材料的内部结构。根据所选的横截面模型，爪的弯曲应力评估为143.4-684.2 MPa。从这些不同的方法的数据使我们提出了一个模型，解释增加纹理粗糙度的摩擦力的饱和。这些力由表面粗糙度R（a）（或平均粒径）和爪尖直径的相对大小决定。当表面粗糙度远大于爪尖直径时，甲虫可以抓住表面不规则性，并由于与基材纹理的机械联锁而产生高度附着。当R（a）小于或等于爪尖端直径时，爪与基底颗粒之间的接触的摩擦性质在摩擦力的产生中起关键作用。
This paper studies slide-resisting forces generated by claws in the free-walking beetle Pachnoda marginata (Coleoptera, Scarabaeoidea) with emphasis on the relationship between the dimension of the claw tip and the substrate texture. To evaluate the force range by which the claw can interact with a substrate, forces generated by the freely moving legs were measured using a load cell force transducer. To obtain information about material properties of the claw, its mechanical strength was tested in a fracture experiment, and the internal structure of the fractured claw material was studied by scanning electron microscopy. The bending stress of the claw was evaluated as 143.4-684.2 MPa, depending on the cross-section model selected. Data from these different approaches led us to propose a model explaining the saturation of friction force with increased texture roughness. The forces are determined by the relative size of the surface roughness R(a) (or an average particle diameter) and the diameter of the claw tip. When surface roughness is much bigger than the claw tip diameter, the beetle can grasp surface irregularities and generate a high degree of attachment due to mechanical interlocking with substrate texture. When R(a) is lower than or comparable to the claw tip diameter, the frictional properties of the contact between claw and substrate particles play a key role in the generation of the friction force.