Spherical Motor Eliminates Robot’s Mechanical Drive System

The spherical induction motor eliminates the robot's mechanical drive system. The SIMbot robot features an elegant motor with just one moving part: the ball. The only other active moving part of the robot is the body itself. A spherical induction motor (SIM) eliminates the mechanical drive system and can move the ball in any direction using only electronic controls. These movements keep SIMbot’s body balanced atop the ball.

Posted in: News, Motors & Drives


New Steel Enables Better Electric Motors

Jun Cui of Iowa State University’s Ames Laboratory works with a metal spinner, which rapidly solidifies metal into thin ribbons. (Photo by Christopher Gannon) In order to make plug-in electric vehicles as affordable and convenient as internal-combustion cars, their motors must be smaller, lighter, more powerful, and more cost-effective. A research team is working to develop motors with the stator core (a non-rotating, magnetic part) manufactured with thin layers of a new “electrical steel.”

Posted in: News, Motors & Drives


Researchers Make Full-Color Holograms from Nanomaterials

Imagine cell phones with 3D floating displays, or credit cards with three-dimensional security markings.By using just one layer of nanoscale metallic film, researchers at Missouri University of Science and Technology have reconstructed 3D full-color holographic images. The technique supports biomedical, security, and big-data storage applications.

Posted in: News


4D Printing: New dimension for additive manufacturing

A team of Lawrence Livermore National Laboratory researchers have demonstrated the 3D printing of shape-shifting structures that can fold or unfold to reshape themselves when exposed to heat or electricity. The micro-architected structures are fabricated from a conductive, environmentally responsive polymer ink developed at the lab.Scientists and engineers revealed their strategy for creating boxes, spirals, and spheres from shape memory polymers (SMPs), bio-based "smart" materials that exhibit shape changes when resistively heated or when exposed to the appropriate temperature. While the approach of using responsive materials in 3D printing, often known as 4D printing, is not new, LLNL researchers are the first to combine the process of 3D printing and subsequent folding (via origami methods) with conductive smart materials to build complex structures.The researchers create primary shapes from an ink made from soybean oil, additional co-polymers, and carbon nanofibers and "program" them into a temporary shape at an engineered temperature determined by chemical composition. Then the shape-morphing effect is induced by ambient heat or by heating the material with an electrical current, which reverts the part's temporary shape back to its original shape."It's like baking a cake," said Jennifer Rodriguez, a postdoc in LLNL's Materials Engineering Division. "You take the part out of the oven before it's done and set the permanent structure of the part by folding or twisting after an initial gelling of the polymer."Ultimately, Rodriguez said, researchers can use the materials to create extremely complex parts. "If we printed a part out of multiple versions of these formulations, with different transition temperatures, and run it through a heating ramp, they would expand in a segmented fashion and unpack into something much more complex."Through a direct-ink writing 3D printing process, the team produced several types of structures: a bent conductive device that morphed to a straight device when exposed to an electric current or heat, a collapsed stent that expanded after being exposed to heat, and boxes that either opened or closed when heated.The technology, the researchers said, could have applications in the medical field, in aerospace (in solar arrays or antennae that can unfold), as well as flexible circuits and robotic devices.

Posted in: News, Manufacturing & Prototyping


Lattice structure absorbs vibrations

Strong vibrations from a bus engine can be felt uncomfortably through the seats. Similarly, vibrations from the propellers or rotors in propeller aircraft and helicopters can make the flight bumpy and loud. They also lead to increased fatigue damage of the aircraft and its components. Engineers have therefore sought to prevent such vibrations in machines, vehicles, and aircraft. A new three-dimensional lattice structure developed by ETH scientists could now expand the possibilities of vibration absorption. Led by Chiara Daraio, Professor of Mechanics and Materials, the researchers made the structure with a lattice spacing of around 3.5 mm out of plastic using a 3D printer. Inside the lattice they embedded steel cubes that are somewhat smaller than dice and act as resonators. "Instead of the vibrations traveling through the whole structure, they are trapped by the steel cubes and the inner plastic grid rods, so the other end of the structure does not move," explains Kathryn Matlack, a postdoc in Daraio's group.The vibration-absorbing structure is rigid and thus can be used as a load-bearing component in rotors and propellers. It also offers another advantage. Compared to existing soft absorption materials, it can absorb a much wider range of vibrations, both fast and slow, and is particularly good at absorbing relatively slow vibrations. "The structure can be designed to absorb vibrations with oscillations of a few hundred to a few tens of thousand times per second (Hertz)," says Daraio. "This includes vibrations in the audible range. In engineering practice, these are the most undesirable, as they cause environmental noise pollution and reduce the energy efficiency of machines and vehicles."In theory, it would be possible to build such a construction out of aluminum and other lightweight metals instead of plastic, says Matlack. In principle, it would just require a combination of lightweight material, structured in a lattice geometry, and embedded resonators with a larger mass density. The geometry of the lattice structure and the resonators would need to be optimally aligned to the anticipated vibrations.The vibration absorbers are essentially ready for technical applications, says Matlack, but they are limited insofar as 3D printing technology is mostly geared toward small-scale production, and material properties, such as the load-bearing capacity, cannot yet match those of components manufactured with traditional methods. Once this technology is ready for industrial use, there is nothing standing in the way of a broader application. A further application could be in wind turbine rotors, where minimizing vibrations would increase efficiency. The technology could also conceivably be used in vehicle and aircraft construction as well as rockets.

Posted in: News, Aerospace


Carbon nanotube 'stitches' make stronger, lighter composites

The newest Airbus and Boeing passenger jets flying today are made primarily from advanced composite materials such as carbon fiber reinforced plastic – extremely light, durable materials that reduce the overall weight of the plane by as much as 20 percent compared to aluminum-bodied planes. Such lightweight airframes translate directly to fuel savings, which is a major point in advanced composites' favor.But composite materials are also surprisingly vulnerable: While aluminum can withstand relatively large impacts before cracking, the many layers in composites can break apart due to relatively small impacts – a drawback that is considered the material's Achilles' heel.Now MIT aerospace engineers have found a way to bond composite layers in such a way that the resulting material is substantially stronger and more resistant to damage than other advanced composites.The researchers fastened the layers of composite materials together using carbon nanotubes – atom-thin rolls of carbon that, despite their microscopic stature, are incredibly strong. They embedded tiny "forests" of carbon nanotubes within a glue-like polymer matrix and then pressed the matrix between layers of carbon fiber composites. The nanotubes, resembling tiny, vertically aligned stitches, worked themselves within the crevices of each composite layer, serving as a scaffold to hold the layers together.In experiments to test the material's strength, the team found that, compared with existing composite materials, the stitched composites were 30 percent stronger, withstanding greater forces before breaking apart.Roberto Guzman, who led the work as an MIT postdoc in the Department of Aeronautics and Astronautics (AeroAstro), says the improvement may lead to stronger, lighter airplane parts – particularly those that require nails or bolts, which can crack conventional composites."More work needs to be done, but we are really positive that this will lead to stronger, lighter planes," says Guzman, who is now a researcher at the IMDEA Materials Institute in Spain. "That means a lot of fuel saved, which is great for the environment and for our pockets."

Posted in: News, Aviation


New System Allows Buildings to 'Sense' Internal Damage

Researchers at the Massachusetts Institute of Technology have developed a computational model that makes sense of the ambient vibrations that travel up a structure as trucks and other forces rumble by. By picking out specific features in the noise that give indications of a building’s stability, the model may be used to continuously monitor a building for signs of damage or mechanical stress.

Posted in: News, Data Acquisition, Detectors, Sensors


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