Massachusetts Institute of Technology

Massachusetts Institute of Technology (4)

MIT Professional Education has added Additive Manufacturing: From 3D Printing to the Factory Floor to their Short Programs offerings. Designed for US and international manufacturing and design engineers, science, and architect professionals who seek the MIT experience in a condensed timeframe, the course will focus on a comprehensive overview of additive manufacturing spanning from fundamentals to applications and technology trends.

Enrollment is now open to qualifying professionals from the U.S. and abroad through the MIT Professional Education website.

The course will be held July 21 – 25 on MIT’s campus in Cambridge, Mass. and will be taught by John Hart, Associate Professor of Mechanical Engineering and Mitsui Career Development Chair at MIT.

“Additive manufacturing covers many application areas including aerospace components, electronics, medical devices, architectural designs, and consumer products,” said Hart. “Participants will take part in lab sessions that will provide a hands-on experience with a variety of state-of-the-art desktop 3D printers.”

“Our Short Programs courses give professionals from around the world the opportunity to learn from MIT faculty who are leaders in their field,” said Anna M. Mahr, director of Short Programs at MIT Professional Education. “They then take home valuable skills and working knowledge that can be applied directly to their work.”

MIT Professional Education provides a variety of education and professional training programs for science, engineering, and technology professionals worldwide. MIT Short Programs offer professionals more than 40 industry focused two to five-day sessions, taking place primarily in the summer on their campus in Cambridge, Mass. Participants learn from leading MIT faculty and gain crucial knowledge to help fuel their careers or enhance their companies in a collaborative academic setting. Upon completion, participants receive an MIT Professional Education certificate of completion, continuing education units, and access to MIT Professional Education’s expansive professional alumni network.

In addition to Additive Manufacturing: From 3D Printing to the Factory Floor, new Short Programs for summer 2014 include Beyond Smart Cities; Engineering Leadership for Mid-Career Professionals; and Understanding and Predicting Technological Innovation: New Data and Theory.

MIT Professional Education also offers national and international professionals the capability to take Short Programs courses abroad, regular MIT academic courses offered through the Advanced Study Program, online courses, or customize an educational experience for a group of employees at a company site. Students are drawn from across the U.S. and around the world, and about 30 percent are international.

For 65 years MIT Professional Education has been providing those professionals engaged in engineering, science and technology worldwide, a gateway to renowned MIT research, knowledge and expertise through advanced education programs designed specifically for working professionals.

For more information, visit: web.mit.edu/professional

Tuesday, 18 June 2013 10:02

Researchers 3D Printing Artificial Bones

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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.

Written by: Denise Brehm, Civil and Environmental Engineering

Imagine that you have a big box of sand in which you bury a tiny model of a footstool. A few seconds later, you reach into the box and pull out a full-size footstool: The sand has assembled itself into a large-scale replica of the model.

That may sound like a scene from a Harry Potter novel, but it’s the vision animating a research project at the Distributed Robotics Laboratory (DRL) at MIT’s Computer Science and Artificial Intelligence Laboratory. At the IEEE International Conference on Robotics and Automation in May — the world’s premier robotics conference — DRL researchers will present a paper describing algorithms that could enable such “smart sand.” They also describe experiments in which they tested the algorithms on somewhat larger particles — cubes about 10 millimeters to an edge, with rudimentary microprocessors inside and very unusual magnets on four of their sides.

Unlike many other approaches to reconfigurable robots, smart sand uses a subtractive method, akin to stone carving, rather than an additive method, akin to snapping LEGO blocks together. A heap of smart sand would be analogous to the rough block of stone that a sculptor begins with. The individual grains would pass messages back and forth and selectively attach to each other to form a three-dimensional object; the grains not necessary to build that object would simply fall away. When the object had served its purpose, it would be returned to the heap. Its constituent grains would detach from each other, becoming free to participate in the formation of a new shape.

Distributed intelligence

Algorithmically, the main challenge in developing smart sand is that the individual grains would have very few computational resources. “How do you develop efficient algorithms that do not waste any information at the level of communication and at the level of storage?” asks Daniela Rus, a professor of computer science and engineering at MIT and a co-author on the new paper, together with her student Kyle Gilpin. If every grain could simply store a digital map of the object to be assembled, “then I can come up with an algorithm in a very easy way,” Rus says. “But we would like to solve the problem without that requirement, because that requirement is simply unrealistic when you’re talking about modules at this scale.” Furthermore, Rus says, from one run to the next, the grains in the heap will be jumbled together in a completely different way. “We’d like to not have to know ahead of time what our block looks like,” Rus says.

Conveying shape information to the heap with a simple physical model — such as the tiny footstool — helps address both of these problems. To get a sense of how the researchers’ algorithm works, it’s probably easiest to consider the two-dimensional case. Picture each grain of sand as a square in a two-dimensional grid. Now imagine that some of the squares — say, in the shape of a footstool— are missing. That’s where the physical model is embedded.

According to Gilpin-author on the new paper, the grains first pass messages to each other to determine which have missing neighbors. (In the grid model, each square could have eight neighbors.) Grains with missing neighbors are in one of two places: the perimeter of the heap or the perimeter of the embedded shape.

Once the grains surrounding the embedded shape identify themselves, they simply pass messages to other grains a fixed distance away, which in turn identify themselves as defining the perimeter of the duplicate. If the duplicate is supposed to be 10 times the size of the original, each square surrounding the embedded shape will map to 10 squares of the duplicate’s perimeter. Once the perimeter of the duplicate is established, the grains outside it can disconnect from their neighbors.

Rapid prototyping

The same algorithm can be varied to produce multiple, similarly sized copies of a sample shape, or to produce a single, large copy of a large object. “Say the tire rod in your car has sheared,” Gilpin says. “You could duct tape it back together, put it into your system and get a new one.”

The cubes — or “smart pebbles” — that Gilpin and Rus built to test their algorithm enact the simplified, two-dimensional version of the system. Four faces of each cube are studded with so-called electropermanent magnets, materials that can be magnetized or demagnetized with a single electric pulse. Unlike permanent magnets, they can be turned on and off; unlike electromagnets, they don’t require a constant current to maintain their magnetism. The pebbles use the magnets not only to connect to each other but also to communicate and to share power. Each pebble also has a tiny microprocessor, which can store just 32 kilobytes of program code and has only two kilobytes of working memory.

The pebbles have magnets on only four faces, Gilpin explains, because, with the addition of the microprocessor and circuitry to regulate power, “there just wasn’t room for two more magnets.” But Gilpin and Rus performed computer simulations showing that their algorithm would work with a three-dimensional block of cubes, too, by treating each layer of the block as its own two-dimensional grid. The cubes discarded from the final shape would simply disconnect from the cubes above and below them as well as those next to them.

True smart sand, of course, would require grains much smaller than 10-millimeter cubes. But according to Robert Wood, an associate professor of electrical engineering at Harvard University, that’s not an insurmountable obstacle. “Take the core functionalities of their pebbles,” says Wood, who directs Harvard’s Microrobotics Laboratory. “They have the ability to latch onto their neighbors; they have the ability to talk to their neighbors; they have the ability to do some computation. Those are all things that are certainly feasible to think about doing in smaller packages.”

“It would take quite a lot of engineering to do that, of course,” Wood cautions. “That’s a well-posed but very difficult set of engineering challenges that they could continue to address in the future.”

For more information, visit: groups.csail.mit.edu/drl/wiki/index.php?title=Robot_Pebbles

Tuesday, 14 February 2012 11:13

MITx prototype course opens for enrollment

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In December, MIT announced the launch of an online learning initiative called “MITx.” Starting this week, interested learners can now enroll for free in the initiative’s prototype course — 6.002x: Circuits and Electronics.

Students can sign up for the course at mitx.mit.edu. The course will officially begin on March 5 and run through June 8.

Modeled after MIT’s 6.002 — an introductory course for undergraduate students in MIT’s Department of Electrical Engineering and Computer Science (EECS) — 6.002x will introduce engineering in the context of the lumped circuit abstraction, helping students make the transition from physics to the fields of electrical engineering and computer science. It will be taught by Anant Agarwal, EECS professor and director of MIT’s Computer Science and Artificial Intelligence Laboratory (CSAIL); Chris Terman, CSAIL co-director; EECS Professor Gerald Sussman; and CSAIL Research Scientist Piotr Mitros.

“We are very excited to begin MITx with this prototype class,” says MIT Provost L. Rafael Reif. “We will use this prototype course to optimize the tools we have built by soliciting and acting on feedback from learners.”

To access the course, registered students will log in at mitx.mit.edu, where they will find a course schedule, an e-textbook for the course, and a discussion board. Each week, students will watch video lectures and demonstrations, work with practice exercises, complete homework assignments, and participate in an online interactive lab specifically designed to replicate its real-world counterpart. Students will also take exams and be able to check their grades as they progress in the course. Overall, students can expect to spend approximately 10 hours each week on the course.

“We invite you to join us for this pilot course of MITx,” Agarwal says. “The 6.002x team of professors and teaching assistants is excited to work with you on the discussion forum, and we look forward to your feedback to improve the learning experience.”

At the end of the prototype course, students who demonstrate their mastery will be able to receive a certificate of completion for free. In future MITx courses, students who complete the mastery requirement on MITx will be able to receive the credential for a modest fee.

Further courses are expected to become available beginning in the fall.

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