Featured Research

from universities, journals, and other organizations

Artificial bone: Designing synthetic materials and quickly turning the design into reality with 3-D printing

Date:
June 17, 2013
Source:
Massachusetts Institute of Technology
Summary:
Researchers have developed a new method to design synthetic materials and quickly turn the design into reality using computer optimization and 3-D printing.

This photo shows the brick-and-mortar pattern of simulated bone and nacre against the backdrop of real nacre found in the inner shell of many molluscs.
Credit: Graham Bratzel; Creative Commons License

Researchers working to design new materials that are durable, lightweight and environmentally sustainable are increasingly looking to natural composites, such as bone, for inspiration: Bone is strong and tough because its two constituent materials, soft collagen protein and stiff hydroxyapatite mineral, are arranged in complex hierarchical patterns that change at every scale of the composite, from the micro up to the macro.

While researchers have come up with hierarchical structures in the design of new materials, going from a computer model to the production of physical artifacts has been a persistent challenge. This is because the hierarchical structures that give natural composites their strength are self-assembled through electrochemical reactions, a process not easily replicated in the lab.

Now researchers at MIT have developed an approach that allows them to turn their designs into reality. In just a few hours, they can move directly from a multiscale computer model of a synthetic material to the creation of physical samples.

In a paper published online June 17 in Advanced Functional Materials, associate professor Markus Buehler of the Department of Civil and Environmental Engineering and co-authors describe their approach. Using computer-optimized designs of soft and stiff polymers placed in geometric patterns that replicate nature's own patterns, and a 3-D printer that prints with two polymers at once, the team produced samples of synthetic materials that have fracture behavior similar to bone. One of the synthetics is 22 times more fracture-resistant than its strongest constituent material, a feat achieved by altering its hierarchical design.

Two are stronger than one

The collagen in bone is too soft and stretchy to serve as a structural material, and the mineral hydroxyapatite is brittle and prone to fracturing. Yet when the two combine, they form a remarkable composite capable of providing skeletal support for the human body. The hierarchical patterns help bone withstand fracturing by dissipating energy and distributing damage over a larger area, rather than letting the material fail at a single point.

"The geometric patterns we used in the synthetic materials are based on those seen in natural materials like bone or nacre, but also include new designs that do not exist in nature," says Buehler, who has done extensive research on the molecular structure and fracture behavior of biomaterials. His co-authors are graduate students Leon Dimas and Graham Bratzel, and Ido Eylon of the 3-D printer manufacturer Stratasys. "As engineers we are no longer limited to the natural patterns. We can design our own, which may perform even better than the ones that already exist."

The researchers created three synthetic composite materials, each of which is one-eighth inch thick and about 5-by-7 inches in size. The first sample simulates the mechanical properties of bone and nacre (also known as mother of pearl). This synthetic has a microscopic pattern that looks like a staggered brick-and-mortar wall: A soft black polymer works as the mortar, and a stiff blue polymer forms the bricks. Another composite simulates the mineral calcite, with an inverted brick-and-mortar pattern featuring soft bricks enclosed in stiff polymer cells. The third composite has a diamond pattern resembling snakeskin. This one was tailored specifically to improve upon one aspect of bone's ability to shift and spread damage.

A step toward 'metamaterials'

The team confirmed the accuracy of this approach by putting the samples through a series of tests to see if the new materials fracture in the same way as their computer-simulated counterparts. The samples passed the tests, validating the entire process and proving the efficacy and accuracy of the computer-optimized design. As predicted, the bonelike material proved to be the toughest overall.

"Most importantly, the experiments confirmed the computational prediction of the bonelike specimen exhibiting the largest fracture resistance," says Dimas, who is the first author of the paper. "And we managed to manufacture a composite with a fracture resistance more than 20 times larger than its strongest constituent."

According to Buehler, the process could be scaled up to provide a cost-effective means of manufacturing materials that consist of two or more constituents, arranged in patterns of any variation imaginable and tailored for specific functions in different parts of a structure. He hopes that eventually entire buildings might be printed with optimized materials that incorporate electrical circuits, plumbing and energy harvesting. "The possibilities seem endless, as we are just beginning to push the limits of the kind of geometric features and material combinations we can print," Buehler says.

The work was funded by the U.S. Army Research Office.


Story Source:

The above story is based on materials provided by Massachusetts Institute of Technology. The original article was written by Denise Brehm. Note: Materials may be edited for content and length.


Journal Reference:

  1. Leon S. Dimas, Graham H. Bratzel, Ido Eylon, Markus J. Buehler. Tough Composites Inspired by Mineralized Natural Materials: Computation, 3D printing, and Testing. Advanced Functional Materials, 2013; DOI: 10.1002/adfm.201300215

Cite This Page:

Massachusetts Institute of Technology. "Artificial bone: Designing synthetic materials and quickly turning the design into reality with 3-D printing." ScienceDaily. ScienceDaily, 17 June 2013. <www.sciencedaily.com/releases/2013/06/130617122359.htm>.
Massachusetts Institute of Technology. (2013, June 17). Artificial bone: Designing synthetic materials and quickly turning the design into reality with 3-D printing. ScienceDaily. Retrieved September 1, 2014 from www.sciencedaily.com/releases/2013/06/130617122359.htm
Massachusetts Institute of Technology. "Artificial bone: Designing synthetic materials and quickly turning the design into reality with 3-D printing." ScienceDaily. www.sciencedaily.com/releases/2013/06/130617122359.htm (accessed September 1, 2014).

Share This




More Matter & Energy News

Monday, September 1, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Australian Airlines Relax Phone Ban Too

Australian Airlines Relax Phone Ban Too

Reuters - Business Video Online (Aug. 26, 2014) Qantas and Virgin say passengers can use their smartphones and tablets throughout flights after a regulator relaxed a ban on electronic devices during take-off and landing. As Hayley Platt reports the move comes as the two domestic rivals are expected to post annual net losses later this week. Video provided by Reuters
Powered by NewsLook.com
Hurricane Marie Brings Big Waves to California Coast

Hurricane Marie Brings Big Waves to California Coast

Reuters - US Online Video (Aug. 26, 2014) Huge waves generated by Hurricane Marie hit the Southern California coast. Rough Cut (no reporter narration). Video provided by Reuters
Powered by NewsLook.com
Chinese Researchers Might Be Creating Supersonic Submarine

Chinese Researchers Might Be Creating Supersonic Submarine

Newsy (Aug. 26, 2014) Chinese researchers have expanded on Cold War-era tech and are closer to building a submarine that could reach the speed of sound. Video provided by Newsy
Powered by NewsLook.com
Breakingviews: India Coal Strained by Supreme Court Ruling

Breakingviews: India Coal Strained by Supreme Court Ruling

Reuters - Business Video Online (Aug. 26, 2014) An acute coal shortage is likely to be aggravated as India's supreme court declared government coal allocations illegal, says Breakingviews' Peter Thal Larsen. Video provided by Reuters
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins