Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

New ultrastiff, ultralight material developed

20.06.2014

Nanostructured material based on repeating microscopic units has record-breaking stiffness at low density.

What's the difference between the Eiffel Tower and the Washington Monument?

Both structures soar to impressive heights, and each was the world's tallest building when completed. But the Washington Monument is a massive stone structure, while the Eiffel Tower achieves similar strength using a lattice of steel beams and struts that is mostly open air, gaining its strength from the geometric arrangement of those elements.

Now engineers at MIT and Lawrence Livermore National Laboratory (LLNL) have devised a way to translate that airy, yet remarkably strong, structure down to the microscale — designing a system that could be fabricated from a variety of materials, such as metals or polymers, and that may set new records for stiffness for a given weight.

The new design is described in the journal Science by MIT's Nicholas Fang; former postdoc Howon Lee, now an assistant professor at Rutgers University; visiting research fellow Qi "Kevin" Ge; LLNL's Christopher Spadaccini and Xiaoyu "Rayne" Zheng; and eight others.

The design is based on the use of microlattices with nanoscale features, combining great stiffness and strength with ultralow density, the authors say. The actual production of such materials is made possible by a high-precision 3-D printing process called projection microstereolithography, as a result of the joint research collaboration between the Fang and Spadaccini groups since 2008.

Normally, Fang explains, stiffness and strength declines with the density of any material; that's why when bone density decreases, fractures become more likely. But using the right mathematically determined structures to distribute and direct the loads — the way the arrangement of vertical, horizontal, and diagonal beams do in a structure like the Eiffel Tower — the lighter structure can maintain its strength.

A pleasant surprise

The geometric basis for such microstructures was determined more than a decade ago, Fang says, but it took years to transfer that mathematical understanding "to something we can print, using a digital projection — to convert this solid model on paper to something we can hold in our hand." The result was "a pleasant surprise to us," he adds, performing even better than anticipated.

"We found that for a material as light and sparse as aerogel [a kind of glass foam], we see a mechanical stiffness that's comparable to that of solid rubber, and 400 times stronger than a counterpart of similar density. Such samples can easily withstand a load of more than 160,000 times their own weight," says Fang, the Brit and Alex d'Arbeloff Career Development Associate Professor in Engineering Design. So far, the researchers at MIT and LLNL have tested the process using three engineering materials — metal, ceramic, and polymer — and all showed the same properties of being stiff at light weight.

"This material is among the lightest in the world," LLNL's Spadaccini says. "However, because of its microarchitected layout, it performs with four orders of magnitude higher stiffness than unstructured materials, like aerogels, at a comparable density."

Light material, heavy loads

This approach could be useful anywhere there's a need for a combination of high stiffness (for load bearing), high strength, and light weight — such as in structures to be deployed in space, where every bit of weight adds significantly to the cost of launch. But Fang says there may also be applications at smaller scale, such as in batteries for portable devices, where reduced weight is also highly desirable.

Another property of these materials is that they conduct sound and elastic waves very uniformly, meaning they could lead to new acoustic metamaterials, Fang says, that could help control how waves bend over a curved surface.

Others have suggested similar structural principles over the years, such as a proposal last year by researchers at MIT's Center for Bits and Atoms (CBA) for materials that could be cut out as flat panels and assembled into tiny unit cells to make larger structures. But that concept would require assembly by robotic systems that have yet to be developed, says Fang, who has discussed this work with CBA researchers. This technique, he says, uses 3-D printing technology that can be implemented now.

###

The work was supported by the U.S. Defense Advanced Research Projects Agency and LLNL.

Written by David Chandler, MIT News Office

Andrew Carleen | Eurek Alert!

Further reports about: Eiffel LLNL MIT Massachusetts geometric materials projection stiffness structure waves weight

More articles from Materials Sciences:

nachricht Glass's off-kilter harmonies
18.01.2017 | University of Texas at Austin, Texas Advanced Computing Center

nachricht Explaining how 2-D materials break at the atomic level
18.01.2017 | Institute for Basic Science

All articles from Materials Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: How gut bacteria can make us ill

HZI researchers decipher infection mechanisms of Yersinia and immune responses of the host

Yersiniae cause severe intestinal infections. Studies using Yersinia pseudotuberculosis as a model organism aim to elucidate the infection mechanisms of these...

Im Focus: Interfacial Superconductivity: Magnetic and superconducting order revealed simultaneously

Researchers from the University of Hamburg in Germany, in collaboration with colleagues from the University of Aarhus in Denmark, have synthesized a new superconducting material by growing a few layers of an antiferromagnetic transition-metal chalcogenide on a bismuth-based topological insulator, both being non-superconducting materials.

While superconductivity and magnetism are generally believed to be mutually exclusive, surprisingly, in this new material, superconducting correlations...

Im Focus: Studying fundamental particles in materials

Laser-driving of semimetals allows creating novel quasiparticle states within condensed matter systems and switching between different states on ultrafast time scales

Studying properties of fundamental particles in condensed matter systems is a promising approach to quantum field theory. Quasiparticles offer the opportunity...

Im Focus: Designing Architecture with Solar Building Envelopes

Among the general public, solar thermal energy is currently associated with dark blue, rectangular collectors on building roofs. Technologies are needed for aesthetically high quality architecture which offer the architect more room for manoeuvre when it comes to low- and plus-energy buildings. With the “ArKol” project, researchers at Fraunhofer ISE together with partners are currently developing two façade collectors for solar thermal energy generation, which permit a high degree of design flexibility: a strip collector for opaque façade sections and a solar thermal blind for transparent sections. The current state of the two developments will be presented at the BAU 2017 trade fair.

As part of the “ArKol – development of architecturally highly integrated façade collectors with heat pipes” project, Fraunhofer ISE together with its partners...

Im Focus: How to inflate a hardened concrete shell with a weight of 80 t

At TU Wien, an alternative for resource intensive formwork for the construction of concrete domes was developed. It is now used in a test dome for the Austrian Federal Railways Infrastructure (ÖBB Infrastruktur).

Concrete shells are efficient structures, but not very resource efficient. The formwork for the construction of concrete domes alone requires a high amount of...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

12V, 48V, high-voltage – trends in E/E automotive architecture

10.01.2017 | Event News

2nd Conference on Non-Textual Information on 10 and 11 May 2017 in Hannover

09.01.2017 | Event News

Nothing will happen without batteries making it happen!

05.01.2017 | Event News

 
Latest News

A big nano boost for solar cells

18.01.2017 | Power and Electrical Engineering

Glass's off-kilter harmonies

18.01.2017 | Materials Sciences

Toward a 'smart' patch that automatically delivers insulin when needed

18.01.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>