Spontaneous rolling on a 90 degree incline

Fuente: arXiv
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Hauptverfasser: Mitra, Surjyasish, Kim, A-Reum, Zhao, Boxin, Mitra, Sushanta K.
Format: Preprint
Veröffentlicht: 2024
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author Mitra, Surjyasish
Kim, A-Reum
Zhao, Boxin
Mitra, Sushanta K.
author_facet Mitra, Surjyasish
Kim, A-Reum
Zhao, Boxin
Mitra, Sushanta K.
contents On perfectly vertical surfaces, rolling is conventionally deemed impossible without external torque. While various species like geckos and spiders exhibit vertical locomotion, they cannot achieve rolling; instead, they fall. In this study, we demonstrate the spontaneous rolling of an elastic polyacrylamide sphere on an elastic polydimethylsiloxane (PDMS) substrate held vertically at a 90 degree incline, given specific elasticity values for the materials. Our experiments uncover a slow rolling motion induced by a dynamically changing contact diameter and a unique contact asymmetry. The advancing edge behaves like a closing crack, while the receding edge acts as an opening crack. Utilizing adhesion hysteresis theories and crack propagation models, we explain how this contact asymmetry generates the necessary torque and friction to maintain rolling, preventing either pinning or falling. The findings challenge the traditional understanding of vertical surface interactions and open new avenues for exploring soft-on-soft contact systems. This novel phenomenon has potential implications for designing advanced materials and understanding biological locomotion on vertical surfaces.
format Preprint
id arxiv_https___arxiv_org_abs_2411_18840
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Spontaneous rolling on a 90 degree incline
Mitra, Surjyasish
Kim, A-Reum
Zhao, Boxin
Mitra, Sushanta K.
Soft Condensed Matter
Classical Physics
On perfectly vertical surfaces, rolling is conventionally deemed impossible without external torque. While various species like geckos and spiders exhibit vertical locomotion, they cannot achieve rolling; instead, they fall. In this study, we demonstrate the spontaneous rolling of an elastic polyacrylamide sphere on an elastic polydimethylsiloxane (PDMS) substrate held vertically at a 90 degree incline, given specific elasticity values for the materials. Our experiments uncover a slow rolling motion induced by a dynamically changing contact diameter and a unique contact asymmetry. The advancing edge behaves like a closing crack, while the receding edge acts as an opening crack. Utilizing adhesion hysteresis theories and crack propagation models, we explain how this contact asymmetry generates the necessary torque and friction to maintain rolling, preventing either pinning or falling. The findings challenge the traditional understanding of vertical surface interactions and open new avenues for exploring soft-on-soft contact systems. This novel phenomenon has potential implications for designing advanced materials and understanding biological locomotion on vertical surfaces.
title Spontaneous rolling on a 90 degree incline
topic Soft Condensed Matter
Classical Physics
url https://arxiv.org/abs/2411.18840