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]
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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]
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MCE
Jose Andrade
postdocs
Ivan Vlahinic
Jason Marshall
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]
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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]
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EE
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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]
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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]
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GALCIT
MCE
Ares Rosakis
Nadia Lapusta
Vito Rubino
