June 17, 2013
Scientists Use 3D Printer To Print Artificial Bone
Brett Smith for redOrbit.com — Your Universe Online
Instead of looking to simply replace natural structures through artificial means, a group of MIT materials scientists are looking to create nature-inspired structures that actually outperform the original.Using 3D printing technology, MIT scientists have developed a process that allows them to turn designs into physical fracture-resistant, bone-like structures within just a few hours, according to their report in the journal Advanced Functional Materials.
While some of physical samples created by the team fracture similar to bones, one of the synthetic structures hierarchical design was changed such that it is 22 times more fracture-resistant than its strongest component material.
“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,” said study co-author Markus Buehler, an engineering professor at MIT.
“As engineers we are no longer limited to the natural patterns,” he added. “We can design our own, which may perform even better than the ones that already exist.”
In the study, the team created three synthetic composite materials. The first sample simulates the mechanical properties of bone using a staggered brick-and-mortar type wall. Another material replicates the mineral calcite via an inverted brick-and-mortar pattern with soft bricks enclosed in stiff polymer cells. The third material has a diamond pattern designed to improve upon bone´s ability to shift and spread impact damage.
The team tested the physical samples to see if they would fracture in the same way as their computer models. According to the researchers, the samples passed the tests, validating the accuracy of the computer-optimized design.
“Most importantly, the experiments confirmed the computational prediction of the bonelike specimen exhibiting the largest fracture resistance,” said study co-author Leon Dimas, a graduate student at MIT. “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 and modified to design and manufacture a variety of materials that consist of two or more constituents. He noted the process could be used to create a variety of specialized materials that could be tailored for specific functions.
Buehler said he hopes that entire buildings will eventually be printed with optimized materials. Methods could be designed to 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 said.
“My work falls in between these fields, at the interface between the natural and the engineering-built world” he said. “I saw an opportunity to work on projects that could be in useful for both sides. It´s a unique combination to work at this interface, and a good fit for what I was interested in.”