Friday, March 29, 2019

At Micro-scale, Peeling Tape Moves Faster than an F-15 Jet

Most of us are familiar with the screeching noise packing tape makes when it's peeled off a box, as well as the frustration of failing to cleanly remove a label from a new purchase. It turns out that the jerky stop-and-go motion we experience when peeling tape occurs at a microscopic level as well.

GIF generated using image courtesy of Physical Review Letters.
Image Credit: Physical Review Letters/American Physical Society
Scientists exploring the physics of peeling tape have observed that tape detaches from a surface in a series of tiny lines perpendicular to the peeling direction that can travel faster than an F-15 fighter jet.

The researchers captured this action using a high-speed camera with microscopic resolution filming at 300,000 frames per second.

The vertical lines in the video are perpendicular to the peeling direction. The average distance between each line is about the width of a single human hair, and each line ripples across the tape surface at the breakneck but somewhat inconsistent speed of up to 2,000 miles per hour, more than twice the speed of sound.

The researchers ran the experiment multiple times using tapes with different thicknesses, weights and lengths, and peeling from different angles and with different speeds. They found a mathematical relationship between these variables and instabilities caused by the lines during peeling. The new findings and model, which were published last month in the journal Physical Review Letters, may help future engineers create better adhesives for specific applications, such as tapes that can peel smoother or quieter.

The study could also shed light on the physics of rapid fracture processes, such as those that occur in building structure failures and earthquake propagation.

Yuen YiuInside Science

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