3D Reticulated Actuator Inspired by Plant Up-Righting Movement Through a Cortical Fiber Network

oleh: Tom Masselter, Olga Speck, Thomas Speck

Format: Article
Diterbitkan: MDPI AG 2021-05-01

Deskripsi

Since most plant movements take place through an interplay of elastic deformation and strengthening tissues, they are thus ideal concept generators for biomimetic hingeless actuators. In the framework of a biomimetic biology push process, we present the transfer of the functional movement principles of hollow tubular geometries that are surrounded by a net-like structure. Our plant models are the recent genera <i>Ochroma</i> (balsa) and <i>Carica</i> (papaya) as well as the fossil seed fern <i>Lyginopteris oldhamia</i>, which hold a net of macroscopic fiber structures enveloping the whole trunk. Asymmetries in these fiber nets, which are specifically caused by asymmetric growth of the secondary wood, enable the up-righting of inclined <i>Ochroma</i> and <i>Carica</i> stems. In a tubular net-like structure, the fiber angles play a crucial role in stress–strain relationships. When braided tubes are subjected to internal pressure, they become shorter and thicker if the fiber angle is greater than 54.7°. However, if the fiber angle is less than 54.7°, they become longer and thinner. In this article, we use straightforward functional demonstrators to show how insights into functional principles from living nature can be transferred into plant-inspired actuators with linear or asymmetric deformation.