Mechanics of Slender Biological Structures

细长结构在我们的人造世界中无处不在：飞机机翼、液压涡轮机叶片或3D打印细丝都具有比第三个维度大得多的一个或两个维度。同样，自然界也充满了细长结构的例子：树枝和树叶，头发，蜘蛛丝，或细胞膜等，我的研究重点是细长结构的力学，而这个发现计划更具体地关注生物细长结构的形态和流体-结构相互作用（FSI）。形态发生描述了生物细胞如何生长和分裂以形成器官和生物体，即，形状和结构是如何形成的机械力在形态发生中起着重要作用，无论是作为内部负荷还是外部刺激。外力的一个主要来源是FSI。因此，它创造了一个形状和结构的反馈回路，影响FSI，FSI反过来影响形态发生。 具体而言，本发现计划解决了以下问题。海藻是如何生长成各种形状的？它们的水动力环境如何影响它们的生长？植物如何生长？它们只是在压力下像气球一样膨胀细胞，还是它们也会膨胀细胞壁？为什么树在风的作用下会弯曲以减少阻力，但却不会像旗帜一样飘动？摇摆能让草捕获更多的风传花粉吗？同样，振荡是否允许软珊瑚捕获更多的水流携带的食物颗粒？我的方法结合了理论模型，桌面实验的理想化系统，和观察自然系统中获得的框架与生物学家的紧密合作。 从长远来看，回答上述问题对于优化海藻水产养殖、农业、林业和水文至关重要，以最大限度地提高产量并最大限度地减少对环境的影响。这些基础知识将作为风对农作物和森林的损害以及植被覆盖的运河和淹没土地中的水流模型的基本成分。在气候变化和风暴更加频繁的情况下，这一知识将证明更加重要。 将应用工业研究和生物力学结合到一个实验室中，在思想的交叉繁殖方面带来了巨大的协同效益。通过仿生，该发现计划的研究将对自清洁疏水表面，用于组织工程的高表面积分层3D打印长丝，高韧性微结构纤维或层流条件下的振荡增强热交换器等的开发产生直接影响。

Slender structures are ubiquitous in our man-made world: aircraft wings, hydraulic turbine blades, or 3D printing filaments all have one or two dimensions much larger than the third one. Similarly, the natural world is also filled with examples of slender structures: tree branches and leaves, hairs, spider silk, or cellular membranes, etc. My research focuses on the mechanics of slender structures, and this Discovery Program more specifically concerns the morphogenesis and Fluid-Structure Interactions (FSI) of biological slender structures. Morphogenesis describes how biological cells grow and divide to shape organs and organism, i.e., how shape and structure originates. Mechanical forces play a central role in morphogenesis either as internal loads or external stimuli. One predominant source of external forces is FSI. It thus creates a feedback loop of shape and structure influencing FSI, and FSI affecting morphogenesis in return. Specifically, this Discovery Program addresses the following questions. How do seaweeds grow to achieve their variety of shapes? How does their hydrodynamic environment influence their growth? How do plants grow? Do they only inflate their cells like balloons under pressure or do they also swell their cell walls? How come trees bend under the wind to reduce their drag but do not flutter like flags? Does oscillating allow grasses to capture more wind-borne pollen? Similarly, does oscillating allow soft corals to capture more water current-borne food particles? My approach combines theoretical models, table-top experiments of idealised systems, and observations on natural systems obtained in a framework of tight collaboration with biologists. Over the long term, answering the questions above is crucial to optimise seaweed aquaculture, agriculture, forestry, and hydrology to maximise output and minimise our impact on the environment. The fundamental knowledge will serve as the base ingredients for models of wind damages to crops and forests, and water flow in vegetated canals and flooded land. This knowledge will prove ever more important in the context of changing climate and more frequent storms. Combining both applied industrial research and biomechanics into one lab brings in enormous benefits of synergy in terms of cross-breeding of ideas. Through biomimetic, the research in this discovery program will have an immediate impact on the development of self-cleaning hydrophobic surfaces, hierarchical 3D printed filaments with high surface area for tissue engineering, high toughness micro-structured fibers, or oscillation-enhanced heat exchangers for laminar flow conditions, etc.