Curvature-induced stiffening of a fish fin.
Curvature-induced stiffening of a fish fin.
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DOI：
10.1098/rsif.2017.0247
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发表时间：
2017-05
期刊：
影响因子：
--
通讯作者：
Mandre S
中科院分区：
文献类型：
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作者：
Nguyen K;Yu N;Bandi MM;Venkadesan M;Mandre S
鱼类如何在机车机动过程中调节鳍的刚度仍然未知。我们表明，改变鳍的曲率调制其刚度。模拟鳍作为可弯曲的骨射线一起举行的膜，我们推断，鳍曲率表现为相邻射线之间的主要弯曲轴的错位。外力使相邻的射线弯曲并张开，从而拉伸膜。弯曲光线和拉伸薄膜之间的这种耦合是刚度增加的基础。使用三维重建的鲭鱼（Scomber）胸鳍为例，我们计算的刚度范围，这种鳍预计通过改变曲率跨度。三维重建表明，即使在其几何平坦的状态下，由于单个射线的形态，功能曲率嵌入在鳍微结构内。由于推进表面将力传递到周围流体的能力受到其刚度的限制，因此鳍的曲率控制鱼与其周围流体之间的耦合。因此，我们的研究结果提供了机械基础和形态预测的假设，即跨越范围的鳍刚度与行为和生态位的鱼。
How fish modulate their fin stiffness during locomotive manoeuvres remains unknown. We show that changing the fin's curvature modulates its stiffness. Modelling the fin as bendable bony rays held together by a membrane, we deduce that fin curvature is manifested as a misalignment of the principal bending axes between neighbouring rays. An external force causes neighbouring rays to bend and splay apart, and thus stretches the membrane. This coupling between bending the rays and stretching the membrane underlies the increase in stiffness. Using three-dimensional reconstruction of a mackerel (Scomber japonicus) pectoral fin for illustration, we calculate the range of stiffnesses this fin is expected to span by changing curvature. The three-dimensional reconstruction shows that, even in its geometrically flat state, a functional curvature is embedded within the fin microstructure owing to the morphology of individual rays. As the ability of a propulsive surface to transmit force to the surrounding fluid is limited by its stiffness, the fin curvature controls the coupling between the fish and its surrounding fluid. Thereby, our results provide mechanical underpinnings and morphological predictions for the hypothesis that the spanned range of fin stiffnesses correlates with the behaviour and the ecological niche of the fish.