Material Inspired by Chain Mail Transforms from Flexible to Rigid on Command
08-12-21
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]
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APhMS
Chiara Daraio
MCE
Jose Andrade
KNI
Yifan Wang
Liuchi Li
Nano-Architected Material Resists Impact Better Than Kevlar
06-25-21
Julia R. Greer, Ruben F. and Donna Mettler Professor of Materials Science, Mechanics and Medical Engineering; Fletcher Jones Foundation Director of the Kavli Nanoscience Institute, has developed a nano-architected material made from tiny carbon struts that is, pound for pound, more effective at stopping a projectile than Kevlar, a material commonly used in personal protective gear. "The knowledge from this work could provide design principles for ultra-lightweight impact resistant materials for use in efficient armor materials, protective coatings, and blast-resistant shields desirable in defense and space applications," says Greer. [Caltech story]
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MedE
MCE
Julia Greer
KNI
A Pathway to Longer-Lasting Lithium Batteries
08-06-20
The energy density of batteries have been a major challenge for consumer electronics, electric vehicles, and renewable energy sources. Julia R. Greer, Ruben F. and Donna Mettler Professor of Materials Science, Mechanics and Medical Engineering; Fletcher Jones Foundation Director of the Kavli Nanoscience Institute, has made a discovery that could lead to lithium-ion batteries that are both safer and more powerful. Findings provide guidance for how lithium-ion batteries, one of the most common kinds of rechargeable batteries, can safely hold up to 50 percent more energy. "Every power-requiring application would benefit from batteries with lithium instead of graphite anodes because they can power so much more," says Greer. "Lithium is lightweight, it doesn't occupy much space, and it's tremendously energy dense." [Caltech story]
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MCE
Julia Greer
KNI
Microstructures Self-Assemble into New Materials
03-03-20
A new process developed at Caltech makes it possible for the first time to manufacture large quantities of materials whose structure is designed at a nanometer scale—the size of DNA's double helix. Pioneered by Julia R. Greer, Ruben F. and Donna Mettler Professor of Materials Science, Mechanics and Medical Engineering; Fletcher Jones Foundation Director of the Kavli Nanoscience Institute, "nanoarchitected materials" exhibit unusual, often surprising properties—for example, exceptionally lightweight ceramics that spring back to their original shape, like a sponge, after being compressed. Now, a team of engineers at Caltech and ETH Zurich have developed a material that is designed at the nanoscale but assembles itself—with no need for the precision laser assembly. "We couldn't 3-D print this much nanoarchitected material even in a month; instead we're able to grow it in a matter of hours," says Carlos M. Portela, Postdoctoral Scholar. "It is exciting to see our computationally designed optimal nanoscale architectures being realized experimentally in the lab," says Dennis M. Kochmann, Visiting Associate. [Caltech story]
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GALCIT
MedE
MCE
Julia Greer
KNI
Dennis Kochmann
postdocs
Carlos Portela
Researchers Develop New Quantum Algorithm
12-19-19
Austin Minnich, Professor of Mechanical Engineering and Applied Physics, Fernando Brandão, Bren Professor of Theoretical Physics, and Garnet Chan, Bren Professor of Chemistry, have developed an algorithm for quantum computers that will help them find use in simulations in the physical sciences. The new algorithm allows a user to find the lowest energy of a given molecule or material. Many people are interested in how to simulate the ground states of molecules and materials. "If we want to do a simulation of water, we could look at how water behaves after it has been blasted into a plasma—an electrically charged gas—but that's not the state water is usually found in; it is not the ground state of water. Ground states are of special interest in understanding the world under ordinary conditions," says Chan. [Caltech story]
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MCE
KNI
Austin Minnich
Fernando Brandão
Garnet Chan