CAREER: Integrated Research and Education on Bio-Inspired Burrowing

这项学院早期职业发展(Career)计划拨款将促进对自然界中动物高效洞穴机制的科学理解。穴居生物可以栖息在广泛的地下土壤类型中，并通过有节奏地改变其身体形状，采取诸如压裂、挖掘、整体流态化、局部流态化、局部颗粒重排和压实等多种穴居策略。与大多数人造钻探仪相比，蚯蚓和双壳类软体动物等几种不同的物种具有非凡的洞穴效率。为什么体型的动态变化能够促进颗粒土壤的渗透在很大程度上仍是未知的。从地质力学的角度来看，该奖项支持对土壤和具有动态形状的生物启发的穿透体之间的相互作用的发现和基本了解。这项研究对下一代高效地下施工技术和多功能小型地下渗透仪的发展具有潜在的启发作用。应用这些技术可以帮助减少能源消耗和提高生产率；而由生物启发挖掘实现的地下传感网络可以帮助监测基础设施的安全。小型、灵活的地下机器人也可以用于正常的岩土工程现场表征，也可以用于通常由于能源和环境限制而难以到达的区域，例如火星勘探或地球上因自然灾害(例如地震、山体滑坡、洪水等)而液化或损坏的地点。此外，通过这项研究获得的新知识和新技术可以用来加深对动物与沉积物之间的机械相互作用的理解，以及对洞穴生物的生态和进化的阐明。这项研究将成为一个促进学习、教学和培训的平台：这项研究的跨学科和受生物启发的性质是一个理想的外展主题，可以激发K-12学生和公众对STEM教育和研究的热情；将研究方法和结果纳入教学和指导将有助于改善岩土工程的形象，并激发学生对跨学科研究的兴趣。该项目的教育目标是利用这项受生物启发的研究，通过两个主要途径教育不同的受众，包括K-12学生、本科生和研究生以及普通公众：(1)与GLBio合作，GLBio是一个专门从事仿生创新和教育的组织，研究成果将向包括K-12学生和普通公众在内的更广泛的受众传播。与GLBio合作，将开发一个流动互动演示摊位和一个关于挖掘机制的可调整的讲座模块，以教育观众关于仿生学和跨学科研究。推广活动将通过GLBio的网络进行，该网络包括俄亥俄州东北部的学校、动物园和博物馆。(2)将建立俄亥俄州东北部地区岩土工程教育联盟(NeoGeo)，由公立和私立大学以及当地行业合作伙伴组成，以整合教育资源，提高其教育质量。为了促进多样性和平等，在招收研究项目的学生时，将优先考虑来自历史上代表性不足的群体(女性和非裔美国人)的合格学生，以及来自低收入家庭和经济困难地区的学生。该项目的研究目标是通过综合实验和数值模型来研究颗粒材料和具有动态形状的仿生侵彻材料之间的相互作用。掘进的复杂性在于颗粒物料与挖掘机之间边界的时空变化，以及颗粒物料的固流转变。实验数字图像相关(DIC)技术和数值离散元方法(DEM)是描述和模拟颗粒动力学的理想方法，为充分理解这一动态结构-颗粒相互作用问题提供了关键的多尺度信息。在这项研究中，(1)将设计一种利用“人造肌肉”的简单双组件装置来模拟文蛤的挖穴运动学；利用人造肌肉进行的穿透实验将利用DIC提供土壤-挖掘机相互作用的多尺度实地观察；(2)将开发并验证基于DEM的虚拟校准室，它将用于在多个长度和时间尺度上研究更多基本的挖穴机理，以及系统地调查土壤性质、土壤应力状态和挖掘机运动学对挖穴性能的影响。本研究最终将回答以下几个问题：1)对于特定类型的土壤，穿透器形状的变化对穿透效率有何影响？2)在给定穿透器的动力学和运动学的情况下，穿透效率(阻力)与土壤性质之间的关系如何？

This Faculty Early Career Development (CAREER) Program grant will promote the scientific understanding of the highly efficient burrowing mechanisms of animals in the natural world. Burrowing organisms can inhabit a wide range of subsurface soil types, and adopt a variety of burrowing strategies such as fracturing, digging, bulk fluidization, localized fluidization, localized grain rearrangement and compaction, facilitated by rhythmically changing their body shape. Several different species such as earthworms and bivalve mollusks possess extraordinary burrowing efficiency compared to most man-made penetrometers. Why the dynamic change in body shape is able to facilitate penetration in particulate soil is still largely unknown. From a geomechanical perspective, this award supports the discovery and fundamental understanding of the interaction between soil and bio-inspired penetrators with dynamic shapes. This research has potential to inspire the development of next-generation, high-efficiency underground construction technologies and versatile small-scale underground penetrometers. Application of these technologies can help reduce energy consumption and improve productivity; and underground sensing networks enabled by bio-inspired burrowing can help monitor the safety of infrastructure. Small, agile underground robots can also be used for normal geotechnical engineering site characterization, and also regions that are normally difficult to reach due to energy and environmental restrictions, such as the exploration of Mars or sites on Earth that are liquefied or damaged due to natural hazards (e.g., earthquakes, landslides, flooding, etc.). In addition, the new knowledge and techniques obtained through this research can be used to develop an understanding of the mechanical interactions between animal and sediment as well as shed light on the ecology and evolution of burrowing organisms. This research will serve as a platform to promote learning, teaching and training: the interdisciplinary and bio-inspired nature of the research is an ideal outreach topic to generate enthusiasm in K-12 students and the public about STEM education and research; the integration of the research approaches and findings into teaching and mentoring will help improve the image of geotechnical engineering and invoke students' interests in interdisciplinary research. The education objective of this project is to utilize this bio-inspired research to educate various audiences, including K-12 students, undergraduate and graduate students, and the general public, on biomimicry research for geotechnical engineering via two major pathways: (1) Partnering with GLBio, a dedicated organization in biomimicry innovation and education, the research outcomes will be disseminated to a broader audience including K-12 students and the general public. In collaboration with GLBio, a mobile interactive demo booth and an adaptable lecture module on the burrowing mechanism will be developed to educate the audience about biomimicry and interdisciplinary research. Outreach activities will be performed through GLBio's network, which includes schools, zoos, and museums in northeast Ohio. (2) A regional alliance for geotechnical engineering education in northeast Ohio (NEOGeo), involving public and private universities as well as local industry partners, will be established to integrate the educational resources and to improve their educational quality. To promote diversity and equality, priority will be given to qualified students from historically underrepresented groups (females and African-Americans), as well as students from low-income families and economically disadvantaged regions when recruiting students for the research program.The research objective of project is to investigate the interaction between granular materials and bio-inspired penetrators with dynamic shape through integrated experimental and numerical models. The complexity of burrowing lies in the tempo-spatial change in the boundaries between granular materials and the burrower, as well as the solid-flow transition of the granular material. Experimental digital image correlation (DIC) techniques and the numerical discrete element method (DEM) are ideal for characterizing and modeling the granule dynamics, providing key multi-scale information to fully understand this dynamic structure-granule interaction problem. In this research, (1) a simple two-component apparatus utilizing an "artificial muscle" will be designed to mimic the burrowing kinematics of clams; penetration experiments with the artificial clam will provide ground truth multiscale observations of the soil-burrower interaction using DIC; (2) a virtual calibration chamber based on DEM will be developed and validated, and it will be used to investigate more fundamental mechanisms of burrowing at multiple length and time scales, as well as to systematically survey the effects of soil properties, soil stress states and burrower kinematics on burrowing performance. This research will ultimately answer the following questions: 1) Given a certain type of soil, how does the penetrator's changing shape affect the penetration efficiency? 2) Given the penetrator's dynamics and kinematics, how does the penetration efficiency (resistance) correlate to soil properties.