Featured Research

from universities, journals, and other organizations

Physicists discover mechanisms of wrinkle and crumple formation

Date:
June 8, 2012
Source:
University of Massachusetts at Amherst
Summary:
How a featureless sheet develops a complex shape has long remained elusive, but now physicists have identified a fundamental mechanism by which such complex patterns emerge spontaneously.

In recent experiments, Davidovitch and colleagues confirmed their earlier theoretical predictions using an ultra-thin film, just tens of nanometers thick. They say the wrinkle-to-crumple transition reflects a dramatic change called “symmetry breaking” in the distribution of stresses in the sheet.
Credit: UMass Amherst

Smooth wrinkles and sharply crumpled regions are familiar motifs in biological and synthetic sheets, such as plant leaves and crushed foils, say physicists Benny Davidovitch, Narayanan Menon and colleagues at the University of Massachusetts Amherst, but how a featureless sheet develops a complex shape has long remained elusive.

Related Articles


Now, in a cover story of the journal, Proceedings of the National Academy of Sciences, the physicists report that they have identified a fundamental mechanism by which such complex patterns emerge spontaneously.

Davidovitch says they were inspired and moved toward a solution by thinking about how a familiar birthday balloon, made of two circular mylar foils, wrinkles and crumples (two separate processes). The two foils start flat, but when glued together around their edges and injected with helium gas to create higher-than-atmospheric pressure inside, they spontaneously changes shape to accommodate the gas.

"This simple process leads to a fascinating pattern of wrinkles and crumples that emerge spontaneously near the perimeter of each foil," Davidovitch points out. "What we discovered is an unusual sequence of transitions that underlie this and possibly other types of morphological complexity."

In the laboratory, rather than balloons, the researchers including doctoral student Hunter King, who conducted many of the experiments, and postdoctoral researcher Robert Schroll, who carried out theoretical calculations, used microscopically thin films and a drop of water to model the effects they wished to study. They cut a circle of ultra-thin film from a sheet 10,000 times thinner than a piece of paper, only tens of nanometers thick, and place it flat on the water drop nestled in a circular collar, where surface tension holds it in place.

"We then very, very gently inject more and more water into the bubble, very gradually, so it becomes more and more curved without spilling over," says Davidovitch. "When the radius of the drop gets small enough, the thin film starts to develop fine radial wrinkles near its outer perimeter as the water pressure increases If you keep adding pressure, decreasing the radius further, a second transition takes place and the film starts to crumple and to look more like a table cloth, draping with sharp creases over the edge of a flattened top," he adds.

Watching this process through incremental steps, the researchers were able to observe and describe through mathematical formulas how the drop imposes confinement on circles of latitude of the sheet. "The degree of this confinement increases as the drop's radius decreases, and an unusual sequence of transitions can then be observed," says Davidovitch.

With this work the investigators, who had earlier proposed quantitative predictions of wrinkle patterns in ultra-thin sheets by following the principle that such sheets must be free of compression, confirm their theoretical predictions. The current experiments also suggest that the wrinkle-to-crumple transition reflects a dramatic change called "symmetry breaking" in the distribution of stresses in the sheet, rather than just a further disruption of its symmetric shape, Davidovitch points out.

The researchers are now working on new puzzles regarding the formation of crumpled features posed by the experiment.


Story Source:

The above story is based on materials provided by University of Massachusetts at Amherst. Note: Materials may be edited for content and length.


Journal Reference:

  1. H. King, R. D. Schroll, B. Davidovitch, N. Menon. Elastic sheet on a liquid drop reveals wrinkling and crumpling as distinct symmetry-breaking instabilities. Proceedings of the National Academy of Sciences, 2012; DOI: 10.1073/pnas.1201201109

Cite This Page:

University of Massachusetts at Amherst. "Physicists discover mechanisms of wrinkle and crumple formation." ScienceDaily. ScienceDaily, 8 June 2012. <www.sciencedaily.com/releases/2012/06/120608135725.htm>.
University of Massachusetts at Amherst. (2012, June 8). Physicists discover mechanisms of wrinkle and crumple formation. ScienceDaily. Retrieved March 27, 2015 from www.sciencedaily.com/releases/2012/06/120608135725.htm
University of Massachusetts at Amherst. "Physicists discover mechanisms of wrinkle and crumple formation." ScienceDaily. www.sciencedaily.com/releases/2012/06/120608135725.htm (accessed March 27, 2015).

Share This


More From ScienceDaily



More Matter & Energy News

Friday, March 27, 2015

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Amazon Complains U.S. Is Too Slow To Regulate Drones

Amazon Complains U.S. Is Too Slow To Regulate Drones

Newsy (Mar. 25, 2015) Days after getting approval to test certain commercial drones, Amazon says the Federal Aviation Administration is dragging its feet on the matter. Video provided by Newsy
Powered by NewsLook.com
Smartphone Use Changing Our Brain and Thumb Interaction, Say Researchers

Smartphone Use Changing Our Brain and Thumb Interaction, Say Researchers

Reuters - Innovations Video Online (Mar. 25, 2015) European researchers say our smartphone use offers scientists an ideal testing ground for human brain plasticity. Dr Ako Ghosh&apos;s team discovered that the brains and thumbs of smartphone users interact differently from those who use old-fashioned handsets. Jim Drury went to meet him. Video provided by Reuters
Powered by NewsLook.com
China Wants to Export Its Steel Problem

China Wants to Export Its Steel Problem

Reuters - Business Video Online (Mar. 25, 2015) China is facing a crisis with a glut of steel and growing public anger over the pollution created by production. In a move to solve the problem, some steel mills are looking to relocate overseas. Jane Lanhee Lee reports. Video provided by Reuters
Powered by NewsLook.com
Robot Stays on Its Feet Despite Punishment

Robot Stays on Its Feet Despite Punishment

Reuters - Innovations Video Online (Mar. 24, 2015) Robotic engineers have modelled a two-legged robot to be fast and agile like an ostrich. The design is more efficient and stable than bipedal robots built to move like humans, according to its creators who abuse the poor machine to test its skills. Ben Gruber has more. Video provided by Reuters
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:

Strange & Offbeat Stories


Space & Time

Matter & Energy

Computers & Math

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins