Department of Applied Physics and Materials Science - Applied Physics

News & Events


Methods from Weather Forecasting Can Be Adapted to Assess Risk of COVID-19 Exposure


Techniques used in weather forecasting can be repurposed to provide individuals with a personalized assessment of their risk of exposure to COVID-19 or other viruses, according to new research published by Caltech scientists. The technique has the potential to be more effective and less intrusive than blanket lockdowns for combatting the spread of disease, says Tapio Schneider, Theodore Y. Wu Professor of Environmental Science and Engineering; Jet Propulsion Laboratory Senior Research Scientist. [Caltech story]

Tags: research highlights Chiara Daraio ESE Tapio Schneider Oliver Dunbar Lucas Böttcher Dmitry Burov Alfredo Garbuno-Inigo Gregory Wagner Sen Pei Raffaele Ferrari Jeffrey Shaman Jinlong Wu

Material Inspired by Chain Mail Transforms from Flexible to Rigid on Command


Engineers at Caltech and JPL have developed a material inspired by chain mail that can transform from a foldable, fluid-like state into specific solid shapes under pressure. "We wanted to make materials that can change stiffness on command," says Chiara Daraio, G. Bradford Jones Professor of Mechanical Engineering and Applied Physics. "We'd like to create a fabric that goes from soft and foldable to rigid and load-bearing in a controllable way." To explore what materials would work best, Daraio, together with former Caltech postdoctoral researcher Yifan Wang and former Caltech graduate student Liuchi Li (PhD '19) as co-lead authors of the Nature paper, designed a number of configurations of linked particles, from linking rings to linking cubes to linking octahedrons (which resemble two pyramids connected at the base). The materials were 3-D printed out of polymers and even metals, with help from Douglas Hofmann, principal scientist at JPL, which Caltech manages for NASA. These configurations were then simulated in a computer with a model from the group of José E. Andrade, the George W. Housner Professor of Civil and Mechanical Engineering and Caltech's resident expert in the modeling of granular materials. [Caltech story]

Tags: APhMS Chiara Daraio MCE Jose Andrade KNI Yifan Wang Liuchi Li

Self-folding “Rollbot” paves the way for fully untethered soft robots


Chiara Daraio, Professor of Mechanical Engineering and Applied Physics, and colleagues have developed soft robotic systems, inspired by origami, that can move and change shape in response to external stimuli, paving the way for fully untethered soft robots. "This work demonstrates how the combination of responsive polymers in an architected composite can lead to materials with self-actuation in response to different stimuli. In the future, such materials can be programmed to perform ever more complex tasks, blurring the boundaries between materials and robots," said Professor Daraio. [Caltech story]

Tags: research highlights Chiara Daraio MCE APh

Microscopic Devices That Control Vibrations Could Allow Smaller Mobile Devices


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

Professor Daraio Receives Outstanding Alumni Award


Chiara Daraio, Professor of Mechanical Engineering and Applied Physics, has been awarded the UC San Diego Mechanical and Aerospace Engineering Outstanding Alumna Award for her outstanding achievements in mechanical metamaterials and materials science. [Award recipients]

Tags: honors Chiara Daraio MCE APh

No Motor, No Battery, No Problem


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

Building Blocks to Create Metamaterials


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

Engineers Create Artificial Skin That "Feels" Temperature Changes


Chiara Daraio, Professor of Mechanical Engineering and Applied Physics, and colleagues have developed an artificial skin capable of detecting temperature changes using a mechanism similar to the one used by the organ that allows pit vipers to sense their prey. [Caltech story]

Tags: APhMS research highlights Chiara Daraio MCE

Professors Rosakis and Daraio Honored by Society for Experimental Mechanics (SEM)


Ares J. Rosakis, Theodore von Karman Professor of Aeronautics and Mechanical Engineering, is the 2015 recipient of the Sia Nemat-Nasser Medal “for innovative singular theoretical and experimental contributions in dynamic fracture and optical techniques, and their application to rupture faults.” The Sia Nemat-Nasser Medal is awarded by the Society for Experimental Mechanics (SEM) and recognizes an individual for distinguished, innovative, and outstanding work that has realized the impact of experimental mechanics on other scientific and engineering fields through an integrated multidisciplinary research. Professor Rosakis received the award at the 2015 SEM annual conference. At the same event Professor Chiara Daraio and colleagues received the 2015 M. Hetényi Award for best research paper published in Experimental Mechanics. Furthermore, EAS alumnus Hugh Bruck became a 2015 fellow and EAS alumnus John Lambros received the M.M. Frocht Award.

Tags: APhMS honors Chiara Daraio GALCIT Ares Rosakis Hugh Bruck John Lambros

Professor Daraio Wins Presidential Early Career Award


Chiara Daraio, Professor of Aeronautics and Applied Physics, has won a 2012 Presidential Early Career Award for Scientists and Engineers (PECASE). Daraio was recognized for her "pioneering contributions to nonlinear mechanical phenomena in acoustic crystals, granular material, and multifunctional nanostructures, and for mentoring women and providing research opportunities for high school and undergraduate students."

"The entire Caltech community is proud to see Professor Daraio recognized with this presidential honor, not only for her pioneering research accomplishments, but also for her commitment to students and diversity," says Chair Ares Rosakis. "Even though she is near the beginning of her career she already embodies the key attributes of the Division of Engineering and Applied Science at Caltech." [Caltech Release]

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