When many objects make contact, they will adopt some collective behavior. For example, sand particles jam together to form a "solid" aggregate (a beach) that you can walk on, hair collects into locks, and sticks can be arranged to form nests and dams. In all of these cases, the collective behavior depends on both the "granular" nature of the objects, i.e. their tendency to jam or rearrange, and their "elasticity," that is, their tendency to deform in response to load. For example, both sand, which is relatively stiff, and cells, which are relatively soft, can rearrange and "flow," however, jammed aggregates of these objects (beaches and biological tissues) vary drastically in their mechanical properties. Here we will unravel the interplay between elasticity and granularity by first separately considering how individual soft objects deform, and many hard particles jam. We will then combine these behaviors step-by-step. First we will consider a single object (an elastic plate) in contact with a hard ring. Then, we will study rearrangement and deformation in two systems where an aggregate made up of stiff particles comes in contact with slender deformable objects, the former reminiscent of plant roots digging into the dirt, and the latter akin to coffee beans jammed in an air-tight bag. Finally, we will consider a system of slender contacting elastic objects, and find that the collective behavior results in the emergence of order. This thesis will illuminate novel physics and functionalities -- building materials which are reformable in real-time and soft robots which can arbitrarily deform, and along the way we will develop tools that could be used to study such diverse systems as the jamming of fibers such as in felt or a collagen network, the properties of a knitted scarf, and the growth and shape of villi in the gut.
| Identifer | oai:union.ndltd.org:bu.edu/oai:open.bu.edu:2144/46283 |
| Date | 30 May 2023 |
| Creators | Guerra, Arman |
| Contributors | Holmes, Douglas P. |
| Source Sets | Boston University |
| Language | en_US |
| Detected Language | English |
| Type | Thesis/Dissertation |
| Rights | Attribution 4.0 International, http://creativecommons.org/licenses/by/4.0/ |
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