How Friction Evolves During an Earthquake
Professor Ares Rosakis, and colleagues including Professor Nadia Lapusta and Research Scientist Vito Rubino, are studying the way friction changes along a fault during a seismic event by simulating quakes in a lab. "Our unique facility … allows us for the first time to study friction point-wise and without having to assume that sliding occurs uniformly, as is done in classical friction studies," Rosakis explains. Professor Lapusta adds, “some numerical models of earthquake rupture … have used friction laws with slip-velocity dependence… It is gratifying to see those formulations validated by the spontaneous mini-earthquake ruptures in our study. " [Caltech story]
Professor Anatol Roshko Passes Away
Anatol Roshko (MS '47, PhD '52), Theodore von Kármán Professor of Aeronautics, Emeritus, at Caltech, passed away on January 23, 2017. Known for his research in several areas of gas dynamics and fluid mechanics, Professor Roshko made contributions to problems of separated flow, bluff-body aerodynamics, shock-wave boundary-layer interactions, shock-tube technology, and the structure of turbulent shear flows. With pioneering aerodynamics researcher Hans Liepmann, he coauthored the widely used textbook Elements of Gasdynamics, published in 1956. [Caltech story]
The Utility of Instability
Professors Dennis M. Kochmann and Chiara Daraio along with colleagues from Harvard have designed and created mechanical chains made of soft matter that can transmit signals across long distances. Because they are flexible, the circuits could be used in machines such as soft robots or lightweight aircraft constructed from pliable, nonmetallic materials. "Engineers tend to shy away from instability. "Though there are many applications, the fundamental principles that we explore are most exciting to me," Kochmann says. "These nonlinear systems show very similar behavior to materials at the atomic scale but these are difficult to access experimentally or computationally. Now we have built a simple macroscale analogue that mimics how they behave." [Caltech story]
Moriah Bischann Wins SURF Speaking Competition
Material science undergraduate student Moriah Bischann, mentored by aerospace postdoctoral scholar, Dr. Owen Kingstedt, is the winner of the Doris S. Perpall Summer Undergraduate Research Fellowships (SURF) Speaking Competition. She was recognized as the best speakers-out of the 200 students who presented their SURF research. Her summer research focused on exploring the next generation of structural materials. During her ten week SURF project she studied the effects of alloying and processing on the dynamic behavior of magnesium (Mg). This work was done to address the larger question of whether Mg is a useful material for the automotive, aerospace, energy, and defense industries where a material is needed that has low density, but also the strength to withstand high impact forces.