Collaborative Research: Elasto-Granular Interactions Between Morphing Skins and Soils

合作研究：变形皮肤和土壤之间的弹力颗粒相互作用

• 批准号: 2228271
• 负责人: Ali Khosravi
• 金额: $ 28.65万
• 依托单位: Auburn University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-10-01 至 2026-09-30
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2228271&HistoricalAwards=false
• 关键词: Collaborative; Research; Elasto; Granular; Interactions

This award will support research at the intersection of geotechnical engineering and structural mechanics, with an eye toward the realization of flexible burrowing probes for applications including site investigation and underground excavation. Flexible probes and robots typically comprise a linear actuator and a compliant skin – a shell-like structure that is carefully patterned to achieve desired and usually extreme morphing behaviors. As the actuator elongates or shortens, the skin interacts with the surrounding soil, endowing the probe with the capacity of moving through the burrow following bioinspired forms. To overcome limitations imposed by current skin designs, this research introduces the idea of multi-modal skins, that can radially expand while generating pop-up features that induce the anisotropic friction necessary for motion within the burrow. To avoid extensive trial and error in the skin design, this project aims at providing an understanding of the “elasto-granular” interactions between elementary features of such morphing skins (e.g., the pop-up plates that yield anisotropic friction) and granular media. This understanding is leveraged to realize a burrowing probe that will be subjected to extensive tests to evaluate the burrowing performance of the skin and its capacity to interact with the surrounding soil in meaningful ways. The ideas within this project will promote the utilization of flexible geotechnical systems, that leverage structural flexibility to achieve innovative functionalities. Moreover, the knowledge on elasto-granular interactions created in this project can be exported to other fields, such as agriculture and biomedical engineering. Our outreach and educational activities, revolving around the theme of “flexible civil engineering systems”, will give students opportunities to see civil engineering systems under a new light and to understand that flexible structures, like those found in nature, are extremely useful in a variety of civil engineering applications.The primary objective of this research is to provide an understanding of the microscopic and macroscopic interactions between “architected” shape-morphing shells and granular media and to leverage this knowledge to guide the realization of probes for underground burrowing and exploration. To reach this objective, our work aims at exploring the interface between the nonlinear mechanics of flexible structures and the mechanics of granular media and soils. This research will use a holistic approach based on: i) theoretical studies on the skins’ morphing capacity using structural mechanics and kinematic theories; ii) stress predictions using the finite element method; iii) studies on microscopic elasto-granular interactions via discrete element modeling and X-ray CT scan-assisted direct shear experiments; and v) macroscopic validation of skin behavior via visualization tank experiments and discrete-element simulations on the burrowing of a probe equipped with such skin. This project will lay the foundation for the rational application of architected shells as morphing skins for burrowing probes.This project is jointly funded by the Engineering for Civil, Mechanical and Manufacturing Innovation (CMMI) Division and the Established Program to Stimulate Competitive Research (EPSCoR).This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

该奖项将支持岩土工程和结构力学交叉领域的研究，着眼于实现用于现场勘察和地下挖掘等应用的柔性掘进探头。柔性探头和机器人通常由线性致动器和柔性蒙皮（外壳）组成。类似的结构经过精心设计，以实现所需的、通常是极端的变形行为。当执行器伸长或缩短时，皮肤与周围的土壤相互作用，赋予探头在土壤中移动的能力。为了克服当前皮肤设计所带来的限制，这项研究引入了多模式皮肤的想法，它可以径向扩展，同时产生弹出特征，从而产生洞穴内运动所需的各向异性摩擦力。为了避免在皮肤设计中进行大量的试验和错误，该项目旨在提供对这种变形皮肤的基本特征（例如，产生各向异性摩擦的弹出板）和利用这种理解来实现一种穴居探针，该探针将接受广泛的测试，以评估皮肤的穴居性能及其以有意义的方式与周围土壤相互作用的能力。灵活的岩土系统，利用结构灵活性来实现创新功能，该项目中创建的弹粒相互作用知识可以导出到其他领域，例如农业和生物医学工程。以“灵活的土木工程系统”为主题，将使学生有机会从新的角度看待土木工程系统，并了解灵活的结构，就像自然界中发现的结构一样，在各种土木工程应用中非常有用。 主要目标这项研究的目的是提供对“结构化”形状变形贝壳和颗粒介质之间微观和宏观相互作用的理解，并利用这些知识来指导地下挖掘和勘探探测器的实现。为了实现这一目标，我们的工作目标是。在探索界面时这项研究将采用基于以下内容的整体方法：i) 使用结构力学和运动学理论对蒙皮变形能力进行理论研究；ii) 使用有限元进行应力预测。元方法；iii) 通过离散元建模和 X 射线 CT 扫描辅助直接剪切实验研究微观弹性颗粒相互作用；v) 通过可视化罐实验和离散元模拟对蒙皮行为进行宏观验证；配备这种蒙皮的探头的挖掘将为合理应用建筑壳体作为挖掘探头的变形蒙皮奠定基础。该项目由土木、机械和制造创新工程（CMMI）部门和该奖项反映了 NSF 的法定使命，并通过使用基金会的智力价值和更广泛的影响审查标准进行评估，被认为值得支持。