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]
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MCE
Julia Greer
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
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 Climate School
04-20-18
To mark the start of Earth Week, Caltech hosted a two-day series of lectures about climate and climate change, which the organizers dubbed "climate school". The speakers included Professor Austin Minnich whose presentation focused on the myths and misconceptions associated with climate change. "Instead of asking for people to trust us, we should ask them notto trust and instead give them guidance for how they can check out what's going on for themselves," Minnich said. [Caltech story]
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MCE
Austin Minnich
APh
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
