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Mechanics of Insect Adhesion

昆虫粘附机制

基本信息

批准号：
1789608
负责人：
金额：
--
依托单位：
University of Oxford
依托单位国家：
英国
项目类别：
Studentship
财政年份：
2016
资助国家：
英国
起止时间：
2016 至无数据
项目状态：
已结题

来源：
https://gtr.ukri.org/projects?ref=studentship-1789608
关键词：
Mechanics Insect Adhesion

项目摘要

Many insects secrete liquids in order to adhere to surfaces, allowing them to climb vertically and upside-down even on smooth surfaces. However, the details of how this is achieved remain unclear. There are open questions about the nature of the adhesive, as well as the dynamics of operation of the adhesive. This project will focus on developing models of different proposed mechanisms that can be compared with existing data in the biological literature, as well as new experiments from the laboratory of Walter Federle (Zoology, Cambridge). An understanding of the operation of such adhesives is important both from a biological perspective, and also as a first step in exploiting similar mechanisms in man-made adhesives.There are two key strands of the project. The first strand is motivated by the observation that the liquid secretion used by many insects is an emulsion of water droplets in oil. However, the purpose of this emulsion is unclear: does the insect rely on the formation of many capillary bridges that then provide a large adhesive force or is the emulsion instead a way to modify the dynamic properties of the adhesive (for example by giving it a finite yield stress)? I will develop models of such emulsions focussed on understanding the force-displacement response that would be expected if capillary bridges were important. I will also begin to understand how such emulsions age, for example through Ostwald ripening.The second strand concerns the manner in which the fluid is secreted through the sac of the insect's adhesive apparatus. Previously, this has been modelled using simple box-models that neglect some of the important mechanics of the problem. I will develop physically-based models to better understand both this secretion process and how it may be reversed when the insect wishes to detach from a surface: previous experimental observations have suggested that depending on how the insect detaches from the surface, the secretion is either left behind on the surface or removed (presumably being reabsorbed into the insect's adhesive apparatus). This is one example of suspected passive mechanisms in insect adhesion that are not at all understood.The approach that I will adopt will involve the development of a hierarchy of mathematical models to understand how such adhesives operate. Here I will benefit from the existing expertise in the group concerning surface tension-dominated phenomena, particularly as it applies to the deformation of soft objects. I will also ensure that I work closely with experimentalists both in Walter Federle's group and with Robert Style (Materials Science, ETH-Zurich): this will allow me to develop models that are biologically relevant (Federle group), whilst also being able to perform quantitative tests in idealised scenarios (Rob Style). This combination of mathematical techniques (asymptotic analysis and some numerical techniques) tested against real experimental data from biological and idealised systems makes this research both timely and novel.This project falls within the EPSRC Fluid Dynamics research area

许多昆虫会分泌液体以粘附在表面上，即使在光滑的表面上，它们也能垂直和倒立地攀爬。然而，如何实现这一目标的细节仍不清楚。关于粘合剂的性质以及粘合剂的操作动态仍存在悬而未决的问题。该项目将重点开发不同提议机制的模型，这些模型可以与生物学文献中的现有数据以及 Walter Federle 实验室（动物学，剑桥）的新实验进行比较。从生物学角度来看，了解此类粘合剂的操作非常重要，而且也是在人造粘合剂中开发类似机制的第一步。该项目有两个关键部分。第一条线索的动机是观察到许多昆虫使用的液体分泌物是油中水滴的乳液。然而，这种乳液的用途尚不清楚：昆虫是否依赖于许多毛细管桥的形成，从而提供大的粘合力，或者乳液是一种改变粘合剂动态特性的方法（例如，通过赋予其有限的屈服应力）？我将开发此类乳液的模型，重点是了解如果毛细管桥很重要的话，预期会出现力-位移响应。我还将开始了解这种乳液是如何老化的，例如通过奥斯特瓦尔德成熟。第二部分涉及液体通过昆虫粘附装置的囊分泌的方式。以前，这是使用简单的盒模型进行建模的，忽略了问题的一些重要机制。我将开发基于物理的模型，以更好地理解这种分泌过程，以及当昆虫希望从表面分离时，它如何逆转：之前的实验观察表明，根据昆虫如何从表面分离，分泌物要么留在表面，要么被移除（可能被重新吸收到昆虫的粘附装置中）。这是昆虫粘附中疑似被动机制的一个例子，但我们根本不了解这种机制。我将采用的方法将涉及开发一系列数学模型，以了解此类粘合剂的工作原理。在这里，我将受益于小组中有关表面张力主导现象的现有专业知识，特别是当它适用于软物体的变形时。我还将确保与 Walter Federle 小组和 Robert Style（材料科学，苏黎世联邦理工学院）的实验人员密切合作：这将使我能够开发生物学相关的模型（Federle 小组），同时还能够在理想化场景中进行定量测试（Rob Style）。这种数学技术（渐近分析和一些数值技术）的组合，针对生物系统和理想化系统的真实实验数据进行了测试，使这项研究既及时又新颖。该项目属于 EPSRC 流体动力学研究领域