Materials capable of dramatically changing their stiffness along specific directions in response to an external stimulus can enable the design of novel robots that can quickly switch between soft/highly–deformable and rigid/load–bearing states. While the jamming transition in discrete media has recently been demonstrated to be a powerful mechanism to achieve such variable stiffness, the lack of numerical tools capable of predicting the mechanical response of jammed media subjected to arbitrary loading conditions has limited the advancement of jamming-based robots. To overcome this limitation, we introduce a 3D finite–element-based numerical tool that predicts the mechanical response of pressurized, infinitely–extending discrete media subjected to arbitrary loading conditions. We demonstrate the capabilities of our numerical tool by investigating the response of periodic laminar and fibrous media subjected to various types of loadings. We expect this work to foster further numerical studies on jamming–based soft robots and structures by facilitating their design, as well as providing a foundation for combining various types of jamming media to create a new generation of tunable composites.
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Jamming Skins that Control System Rigidity from the Surface
Numerous animals adapt their stiffness during natural motions to increase efficiency or environmental adaptability. For example, octopuses stiffen their tentacles to increase efficiency during reaching, and several species adjust their leg stiffness to maintain stability when running across varied terrain. Inspired by nature, variable‐stiffness machines can switch between rigid and soft states. However, existing variable‐stiffness systems are usually purpose‐built for a particular application and lack universal adaptability. Here, reconfigurable stiffness‐changing skins that can stretch and fold to create 3D structures or attach to the surface of objects to influence their rigidity are presented. These “jamming skins” employ vacuum‐powered jamming of interleaved, discrete planar elements, enabling 2D stretchability of the skin in its soft state. Stretching allows jamming skins to be reversibly shaped into load‐bearing, functional tools on‐demand. Additionally, they can be attached to host structures with complex curvatures, such as robot arms and portions of the human body, to provide support or create a mold. We also show how multiple skins can work together to modify the workspace of a continuum robot by creating instantaneous joints. Jamming skins thus serve as a reconfigurable approach to creating tools and adapting structural rigidity on‐demand.
more » « less- Award ID(s):
- 1830870
- NSF-PAR ID:
- 10375693
- Publisher / Repository:
- Wiley Blackwell (John Wiley & Sons)
- Date Published:
- Journal Name:
- Advanced Functional Materials
- Volume:
- 31
- Issue:
- 1
- ISSN:
- 1616-301X
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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