Caltech's Jose Andrade has been awarded the Walter L. Huber Civil Engineering Research Prize, the highest civil engineering research award aimed at mid-career researchers who have made notable contributions to their discipline.
Andrade, the George W. Housner Professor of Civil and Mechanical Engineering, was recognized by the American Society of Civil Engineers (ASCE), "for revolutionizing the field of granular geo-materials" by creating "rigorous multiscale modeling approaches based on scientific understanding of the mechanics and physics across scales and for defining new frontiers for the civil engineering profession including planetary exploration," according to his award letter.
Andrade, who studies how stresses move through granular materials like sand and soil, characterizes his contribution to the field as a "connecting of scales"—understanding granular materials both at the macro scale, where broad generalizations about how large volumes of grains behave under stress can be made, and at the micro scale, studying how those stresses move between individual grains.
"The state of the art for the last hundred years or more has been to look at things at the macro level, and see how large collections of particles behave. We watch them, we follow them, and we make broad statements about force," Andrade says. About 20 or 30 years ago, researchers started to do experiments and computations at the scale of individual grains. The question was, would it be possible to take this grain-level information and make macro-level predictions—or was this just too complicated?
Maybe not, Andrade thought. About 10 years ago, Andrade and his colleagues began taking advantage of advances in computing to create models that took into account individual grains, but worked at a macro scale. They used a technique called X-ray tomography to make maps of the shape of each grain and chart its relationship to its neighbors in a large group of particles, and then a different technique called X-ray diffraction to show how those grains acted upon one another when under stress.
The result is a broad picture of how granular materials behave under stress that takes into account the transmission of force at the granular level. That level of detail is fantastic for, say, NASA engineers trying to understand whether a rover would get bogged down while traversing the dusty plains of Mars. However, Andrade admits, it is overkill if what you need to do is decide how to build a house on a sandy patch of beachfront property. "I don't think you'll ever do an engineering-scale calculation at the grain-scale level of detail," he says. "What we're trying to do here is not replace the macroscopic average type of calculations that today are the state of the art. We're trying to probe the grain scale at a sufficiently large level of scale so that we can get better understanding and better modeling."
Andrade says he looks forward to continuing to refine and expand models of granular materials, and that improvements in computational abilities will further improve the accuracy and depth of those models.
He will travel to Denver, Colorado in October to receive his award.
Andrade earned his PhD from Stanford in 2006 and has been teaching at Caltech since 2010. Since 2016, he has led the Department of Mechanical and Civil Engineering (MCE) in the Division of Engineering and Applied Science as its executive officer, and was named MCE's Cecil and Sally Drinkward Leadership Chair in 2017.
The ASCE was founded in 1852 and is the nation's oldest engineering society. ASCE represents more than 150,000 members from the civil engineering profession in 177 countries. Its board authorized awards to stimulate research in civil engineering in 1946. In 1964, the award was endowed by Alberta Reed Huber in honor of her husband, Walter L. Huber, a past president of the ASCE.