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New Materials Exhibit Split Personality

02-01-19

Julia Greer, Professor of Materials Science, Mechanics and Medical Engineering, and colleagues have determined that the failure of architected materials—the point at which they break when compressed or stretched—can be described using classical continuum mechanics, which models the behavior of a material as a continuous mass rather than as individual (or "discrete") particles. This finding implies a duality to the nature of these materials—in that they can be thought of both as individual particles and also as a single collective. [Caltech story]

Tags: APhMS research highlights MCE Julia Greer

The Moving Earth, Micro to Mega

01-18-19

Nadia Lapusta, Professor of Mechanical Engineering and Geophysics, creates computer models of earthquakes by integrating an astonishing range of data—on scales from thousands of kilometers down to microns and from millennia down to thousandths of a second. “You have to understand the mechanics across the entire earthquake system, starting at the micrometer scale,” says Professor Lapusta. “This is the challenge.” Her numerical models rely upon field observations, seismic monitoring, lab experiments, and theoretical science, while complementing those endeavors with a new perspective. The predictions expand researchers’ view beyond the limits of direct observation—which is important for events that occur across thousands of years. [Breakthrough story] [ENGenious story]

Tags: research highlights MCE Nadia Lapusta

Microscopic Devices That Control Vibrations Could Allow Smaller Mobile Devices

12-12-18

Chiara Daraio, Professor of Mechanical Engineering and Applied Physics, and colleagues have developed phononic devices that include parts that vibrate extremely fast, moving back and forth up to tens of millions of times per second. The devices were developed by creating silicon nitride drums that are just 90 nanometers thick. The drums are arranged into grids, with different grid patterns having different properties. Professor Daraio, along with former Caltech postdoctoral scholar Jinwoong Cha, have shown that arrays of these drums can act as tunable filters for signals of different frequencies and can act like one-way valves for high-frequency waves. [Caltech story]

Tags: research highlights Chiara Daraio MCE APh postdocs Jinwoong Cha

Nailing It: Caltech Engineers Help Show That InSight Lander Probe Can Hammer Itself Into Martian Soil

11-26-18

Professor José Andrade’s research team including Postdoctoral researchers Ivan Vlahinic and Jason Marshall have helped the InSight Mars lander boldly go where no one has gone before: beneath the surface of Mars. InSight is equipped with two main instrument packages: a seismometer for studying how seismic waves (for example, from marsquakes and meteorite impacts) travel through the planet and a "mole" that will burrow into the ground, dragging a tether with temperature sensors behind it to measure how temperatures change with depth on the planet. These instruments will tell scientists about Mars's interior structure (similar to the way an ultrasound lets doctors "see" inside a human body) and also about the heat flow from the planet's interior. When designing the mole the engineers at JPL wanted to be certain that it would be capable of reaching the necessary depth, and so they called on Professor Andrade, an expert on the physics of granular materials. He was able to develop new computer models that helped the JPL team predict the mole's effectiveness in Martian soil. Unless the mole encounters an obstacle, Andrade is confident that it will be successful. [Caltech story]

Tags: research highlights MCE Jose Andrade postdocs Ivan Vlahinic Jason Marshall

Caltech Awarded Federal Funding for Quantum Research

09-25-18

EAS Professors were among a small group of Caltech scientists and engineering who have won federal grants for research in quantum computing, and quantum networks. Professor Nadj-Perge (lead PI) along with co-PIs Professors Marco Bernardi and Andrei Faraon as well as co-investigator Professor Julia Greer have received funding for the program ”Quantum States in Layered Heterostructures Controlled by Electrostatic Fields and Strain," which is administered within the U.S. Department of Energy's Basic Energy Sciences division. Professor Austin Minnich is a co-PI of the program, "Quantum simulation of materials and molecules using quantum computation," which is part of the National Science Foundation's Research Advanced by Interdisciplinary Science and Engineering (RAISE)-Transformational Advances in Quantum Systems (TAQS) effort. [Caltech story]

Tags: APhMS research highlights MCE Julia Greer Austin Minnich Andrei Faraon Marco Bernardi Stevan Nadj-Perge

President Rosenbaum Highlights Postdocs as "Unsung Heroes"

09-24-18

In a letter to the Caltech community during National Postdoc Appreciation Week, the Caltech President emphasizes the role this key group plays at the Institute. He stated, “Caltech's mission of world-leading research and education depends crucially on our postdoctoral scholars. Although their time at Caltech may be short, they quickly become vital parts of the Institute's intellectual fabric.” [President’s Letter] [EAS Postdoc Resource Page]

Tags: APhMS EE GALCIT MedE MCE CMS ESE Thomas Rosenbaum postdocs

No Motor, No Battery, No Problem

05-15-18

Chiara Daraio, Professor of Mechanical Engineering and Applied Physics, and colleagues have developed robots capable of self-propulsion without using any motors, servos, or power supply. Instead, these first-of-their-kind devices paddle through water as the material they are constructed from deforms with temperature changes. "Combining simple motions together, we were able to embed programming into the material to carry out a sequence of complex behaviors," says Caltech postdoctoral scholar Osama R. Bilal, who is co-first author of the PNAS paper is titled "Harnessing bistability for directional propulsion of soft, untethered robots." [Caltech story]

Tags: research highlights Chiara Daraio MCE APh postdocs Osama Bilal

Caltech and Disney Engineers Collaborate on Robotics

01-18-18

Caltech and Disney Research have entered into a joint research agreement to pioneer robotic control systems and further explore artificial intelligence technologies. Pietro Perona will work with Disney roboticist Martin Buehler to create navigation and perception software that could allow robotic characters to safely move through dense crowds and interact with people. Aaron Ames will work with Disney Research's Lanny Smoot to further explore robot autonomy and machine learning by creating objects that can self-navigate and perform stunts. Yisong Yue has been working with engineers from Disney Research on the use of machine learning to analyze the behavior of soccer players and to measure audience engagement. [Caltech story]

Tags: EE research highlights MCE CMS Pietro Perona Yisong Yue Aaron Ames

Building Blocks to Create Metamaterials

01-17-18

Chiara Daraio, Professor of Mechanical Engineering and Applied Physics, and colleagues have created a method to systematically design metamaterials using principles of quantum mechanics. "Before our work, there was no single, systematic way to design metamaterials that control mechanical waves for different applications," Professor Daraio says. "Instead, people often optimized a design to fulfill a specific purpose, or tried out new designs based on something they saw in nature, and then studied what properties would arise from repeated patterns." [Caltech story]

Tags: research highlights Chiara Daraio MCE APh

How Friction Evolves During an Earthquake

08-15-17

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]

Tags: research highlights GALCIT MCE Ares Rosakis Nadia Lapusta Vito Rubino