From nanocrystals to the Earth's crust, solid materials share similar failure characteristics

Rick Kubetz, Engineering at Illinois
11/17/2015

Professor of Physics Karin Dahmen
Professor of Physics Karin Dahmen
Apparently, size doesn’t always matter. An extensive study by an interdisciplinary research group suggests that the deformation properties of nanocrystals are not much different from those of the Earth’s crust.

“When solid materials such as nanocrystals, bulk metallic glasses, rocks, or granular materials are slowly deformed by compression or shear, they slip intermittently with slip-avalanches similar to earthquakes,” explained Karin Dahmen, a professor of physics at the University of Illinois at Urbana-Champaign. “Typically these systems are studied separately. But we found that the scaling behavior of their slip statistics agree across a surprisingly wide range of different length scales and material structures.”

“Identifying agreement in aspects of the slip statistics is important, because it enables us to transfer results from one scale to another, from one material to another, from one stress to another, or from one strain rate to another,” stated Shivesh Pathak, a physics undergraduate at Illinois, and a co-author of the paper, “Universal Quake Statistics: From Compressed Nanocrystals to Earthquakes,” appearing in Scientific Reports. “The study shows how to identify and explain commonalities in the deformation mechanisms of different materials on different scales.

“The results provide new tools and methods to use the slip statistics to predict future materials deformation,” added Michael LeBlanc, a physics graduate student and co-author of the paper. “They also clarify which system parameters significantly affect the deformation behavior on long length scales. We expect the results to be useful for applications in materials testing, failure prediction, and hazard prevention.”

Researchers representing a broad a range of disciplines—including physics, geosciences, mechanical engineering, chemical engineering, and materials science—from the United States, Germany, and the Netherlands contributed to the study, comparing five different experimental systems, on several different scales, with model predictions.

As a solid is sheared, each weak spot is stuck until the local shear stress exceeds a random failure threshold. It then slips by a random amount until it re-sticks. The released stress is redistributed to all other weak spots. Thus, a slipping weak spot can trigger other spots to fail in a slip avalanche.

Using tools from the theory of phase transitions, such as the renormalization group, one can show that the slip statistics of the model do not depend on the details of the system.

“Although these systems span 13 decades in length scale, they all show the same scaling behavior for their slip size distributions and other statistical properties,” stated Pathak. “Their size distributions follow the same simple (power law) function, multiplied with the same exponential cutoff.”

The cutoff, which is the largest slip or earthquake size, grows with applied force for materials spanning length scales from nanometers to kilometers. The dependence of the size of the largest slip or quake on stress reflects “tuned critical” behavior, rather than so-called self-organized criticality, which would imply stress-independence. 

“The agreement of the scaling properties of the slip statistics across scales does not imply the predictability of individual slips or earthquakes,” LeBlanc said. “Rather, it implies that we can predict the scaling behavior of average properties of the slip statistics and the probability of slips of a certain size, including their dependence on stress and strain-rate.”

Study co-authors include Jonathan Uhl, Xin Liu, Ryan Swindeman, Nir Friedman, University of Illinois at Urbana Champaign; Danijel Schorlemmer and Georg Dresen, German Research Centre for Geosciences; Danijel Schorlemmer and Thorsten Becker, University of Southern California; Robert Behringer, Duke University; Dmitry Denisov and Peter Schall, University of Amsterdam; Xiaojun Gu, Wendelin J. Wright, Xiaojun Gu and Wendelin J. Wright, Bucknell University; Todd Hufnagel, Johns Hopkins University; Andrew Jennings and Julia R. Greer, California Institute of Technology; and P.K. Liaw, The University of Tennessee; Georgios Tsekenis, Harvard, and Braden Brinkman, Seattle, were part of Dahmen's research group during the original study.

Recent News

  • In the Media

As the chair of the NASA Fundamental Physical Sciences  Review Board, which has oversight responsibility for the recently launched Cold Atom Laboratory (CAL), Professor Brian DeMarco plays a seminal role in the "Coolest Experiment in the Universe," taking place on the International Space Station. DeMarco is featured in the video released in conjunction with this press release. The ultra-cold-atom experiment will study a Bose-Einstein condensate in space to uncover a new understanding of its properties and interactions at a temperature barely above absolute zero.

  • Accolades

Professor Peter Abbamonte has been named the Fox Family Professor in Engineering at the University of Illinois at Urbana-Champaign. Named faculty appointments signify a distinction beyond that of professorial rank, recognizing distinguished scholars for their prominence in research, teaching, and service.

  • In the Media

A second solar farm planned in Savoy will put the University of Illinois in the lead among American universities in terms of solar energy, a top campus proponent says.

The campus is moving ahead with a 55-acre solar farm along the north side of Curtis Road, between First and Neil streets in Savoy, about a mile south of the first 21-acre farm on Windsor Road.

Physics Professor Scott Willenbrock, who recently served as a provost's fellow for sustainability, briefed the Academic Senate about the project Monday, saying it will help the campus meet its goal of generating 5 percent of its energy needs from renewable sources. That target was part of the Illinois Climate Action Plan, known as iCap.

  • Research
  • Biological Physics

A previously unappreciated interaction in the genome turns out to have possibly been one of the driving forces in the emergence of advanced life, billions of years ago.

This discovery began with a curiosity for retrotransposons, known as “jumping genes,” which are DNA sequences that copy and paste themselves within the genome, multiplying rapidly. Nearly half of the human genome is made up of retrotransposons, but bacteria hardly have them at all.

Nigel Goldenfeld, Swanlund Endowed Chair of Physics and leader of the Biocomplexity research theme at the IGB, and Thomas Kuhlman, a former physics professor at Illinois who is now at University of California, Riverside, wondered why this is.“We thought a really simple thing to try was to just take one (retrotransposon) out of my genome and put it into the bacteria just to see what would happen,” Kuhlman said. “And it turned out to be really quite interesting.”