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arXiv · 2610.19480

Why shaking faster does not untangle: frequency-selective extraction of filaments from tangled matter

Ishant Tiwari·Sutikshan Bansal·Rosalind Huang·Chenyi Fei·Jörn Dunkel·Vishal Patil·Saad Bhamla
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Abstract

Tangles of soft filaments are ubiquitous, from living worm blobs to the cables in a desk drawer. How do such tangles, held together by friction and entanglement, respond when one embedded filament is shaken? We suspend disordered tangles of tunable cohesion and ordered stitched meshes from a single thread (the tether) and oscillate it vertically at fixed amplitude. Extraction peaks at an intermediate drive frequency ($\sim 15$ Hz) and declines at higher frequencies, although the peak drive acceleration grows quadratically. Here we combine experiments, high-speed imaging, and a tension-only spring-mass model to show that this non-monotonic response is set by timing rather than resonance. The extraction window is bounded below by a slackening threshold, where the peak drive acceleration exceeds gravity and the tether, slack for part of each cycle, creates a tensile impulse each time it snaps taut. The window is bounded above by a transmission crossover, where the transmission time across the tangle exceeds a quarter of the drive cycle, so that the tangle no longer responds as a whole and the drive's work dissipates internally. The slackening threshold depends only on the drive and gravity, while the transmission crossover is set only by the tangle's size and transmission speed. By tracing extraction to the overlap of impulse creation and impulse transmission, we identify a generic principle of driven filamentous matter and suggest frequency-selective routes to its disassembly.

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Ishant Tiwari, Sutikshan Bansal, Rosalind Huang, Chenyi Fei, Jörn Dunkel, Vishal Patil, Saad Bhamla. 2026-10-14. Why shaking faster does not untangle: frequency-selective extraction of filaments from tangled matter. https://arxiv.org/abs/2610.19480

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