MECHANICAL ENGINEERING LATEST RESEARCH UPDATE (Oct. 24, 2013)

Manufacturing in four dimensions is now possible after researchers incorporate ‘shape memory’ polymer fibres into 3D printing. Researchers at the University of Colorado Boulder (CU-Boulder) believe the innovation, which adds a time-dimension to the 3D printing process, will open up possibilities for the creation and use of adaptive, composite materials in manufacturing, packaging and biomedical applications. 

A team led by H. Jerry Qi, associate professor of mechanical engineering at CU-Boulder, and his collaborator Martin Dunn of the Singapore University of Technology and Design introduced the novel fibres into the composite materials used in traditional 3D printing, resulting in the production of an object fixed in one shape that can later be changed to take on a new shape.

“In this work, the initial configuration is created by 3D printing, and then the programmed action of the shape memory fibres creates time dependence of the configuration; the 4D aspect,” said Dunn, a former CU-Boulder mechanical engineering faculty member.

The 4D printing concept, which allows materials to “self-assemble” into 3D structures, was initially proposed by Massachusetts Institute of Technology faculty member Skylar Tibbits in April of this year. Tibbits and his team combined a strand of plastic with a layer made out of “smart” material that could self-assemble in water.

“We advanced this concept by creating composite materials that can morph into several different, complicated shapes based on a different physical mechanism,” said Dunn. “The secret of using shape memory polymer fibres to generate desired shape changes of the composite material is how the architecture of the fibres is designed, including their location, orientation and other factors.” 
The CU-Boulder team’s findings are published in the journal Applied Physics Letters. The paper was co-authored by Qi “Kevin” Ge, who joined MIT as a postdoctoral research associate in September.

“The fascinating thing is that these shapes are defined during the design stage, which was not achievable a few years ago,” said Qi. The CU-Boulder team demonstrated that the orientation and location of the fibres within the composite determines the degree of shape memory effects like folding, curling, stretching or twisting. The researchers also showed the ability to control those effects by heating or cooling the composite material. Qi says 3D printing technology, which has existed for about three decades, has only recently advanced to the point that active fibres can be incorporated into the composites so their behaviour can be predictably controlled when the object is subjected to thermal and mechanical forces.

The technology promises exciting new possibilities for a variety of applications. Qi said that a solar panel or similar product could be produced in a flat configuration onto which functional devices can be easily installed. It could then be changed to a compact shape for packing and shipping. After arriving at its destination, the product could be activated to form a different shape that optimizes its function.
As 3D printing technology matures with more printable materials and higher resolution at larger scales, the researchers hope their work will help provide a new approach to creating reversible or tunable 3D surfaces and solids in engineering like the composite shells of complex shapes used in automobiles, aircraft and antennas.

LATEST MECHANICAL ENGINEERING NEWS (Oct.16, 2013)

LET'S KNOW ALL ABOUT THE LATEST HYPERCAR OF THE WORLD.

If you have some spare cash on hand and are hunting for a vehicle with a little pop in the accelerator, then Koenigsegg Automotive AB may have the car for you. (Just kidding)

Details -- The Swedish automaker’s 2014 Agera S “hypercar” will take you from 0 to 62 mph in a scant 2.9 seconds and will hit a top speed of 260 mph if you have a long straightaway in your backyard. It also offers a V-8 engine that peaks at 1,030 hp and 811 lb-ft of torque, a max lateral acceleration of 1.6 g’s, and a braking package that enables it to decelerate from 62 mph down to zero in just 100 ft. All for a starting price of $1.46 million.
As dazzling as those numbers are, however, the Agera’s most amazing stat may be the size of its engineering staff. “We have between 15 and 20 engineers at any given time, and all of them have to do more than one thing,” Jens Sverdrup, regional director for Koenigsegg Automotive AB, told Design News. “Our software engineers do hardware. We have one engineer who designs our carbon wheels and our electronics. You can’t be a one-trick pony around here.” Indeed, the engineers at Koenigsegg have a full plate. They designed the vehicle’s 5.0 liter, V-8 aluminum engine, front and rear suspensions, carbon-fiber monocoque, carbon-fiber leather-clad interior, and one-of-a-kind carbon-fiber wheels. And along with creating those performance systems, they also configured the car to include all the normal street-legal vehicle amenities, such as airbags, emission components, antilock brakes, electronic stability controls, and countless other necessary sub-systems. ”It’s brutal yet refined,” Sverdrup told us. “It’s an old-school supercar combined with new technology.” From its 1,000-hp engine and Triplex rear suspension to its carbon-fiber wheels and custom-designed electronics.

LATEST MECHANICAL ENGINEERING RESEARCH & NEWS UPDATE (Oct. 18, 2013)

Thermoelectric bracelet: 'Cool' invention wins first place at MADMEC:

What is it, how it works & why it wins? Know all details here:

Details -- Heating or cooling certain parts of your body—such as applying a warm towel to your forehead if you feel chilly—can help maintain your perceived thermal comfort. Using that concept, four MIT engineering students developed a thermoelectric bracelet that monitors air and skin temperature, and sends tailored pulses of hot or cold waveforms to the wrist to help maintain thermal comfort. 

For this invention, the team, called Wristify, took home the $10,000 first prize at this year's Making And Designing Materials Engineering Competition (MADMEC), held Tuesday afternoon.

The product is now a working prototype. And although people would use the device for personal comfort, the team says the ultimate aim is to reduce the energy consumption of buildings, by cooling and heating the individual —not the building. "Buildings right now use an incredible amount of energy just in space heating and cooling. In fact, all together this makes up 16.5 percent of all U.S. primary energy consumption . We wanted to reduce that number, while maintaining individual thermal comfort," says Sam Shames, a mechanical engineering senior who co invented the Wristify technology. "We found the best way to do it was local heating and cooling of parts of the body."
The team estimates that if the device stops one building from adjusting its temperature by even just 1 degree Celsius, it will save roughly 100 kilowatt-hours per month. The annual competition, now in its seventh year, is run by MIT's Department of Materials Science and Engineering (DMSE), and is sponsored by Saint Gobain, BP, and Dow Chemical. The contest's theme this year was "materials science solutions for sustainability."
After the competition, some teams may further develop their products, or even take them to market. But the primary aim of the competition is to engage students in prototyping and design, says Michael Tarkanian, a technical instructor in DMSE who has been a MADMEC judge each year. "The goal is to allow students to get their hands dirty, working in the labs to design and build functional prototypes," he says. "It gives them an opportunity to put their classroom knowledge to work, solving problems related to energy, habitat, and sustainability."

Leveraging human sensitivity:
For the competition, teams of two to five MIT students receive $1,000 to build their prototypes. Starting in June, monthly checkpoints and several independent design challenges are organized to help guide the teams in the development process. Over the course of developing its technology, the Wristify team made a key discovery: Human skin is very sensitive to minute, rapid changes in temperature, which affect the whole body. They found they needed to heat or cool any body part (in their case, the wrist) at a rate of at least 0.1 C per second in order to make the entire body, overall, feel several degrees warmer or colder. After 15 prototypes, the team landed on its final product, which resembles a wristwatch and can be powered, for up to eight hours, by a lithium polymer battery. This prototype demonstrated a rate of change of up to 0.4 C per second. The "watch" part of the prototype actually consists of the team's custom copper alloy-based heat sink (a component that lowers a device's temperature by dissipating heat). Attached is an automated control system that manages the intensity and duration of the thermal pulses delivered to the heat sink. Integrated thermometers also measure external and body temperature to adjust accordingly. "What we developed is a wearable, wrist-based technology that leverages human sensitivity, can detect and perfect rates of change, and can maintain overall thermal comfort while reducing the need to heat and cool buildings," Shames says. With the prize money, the team plans to further develop the prototype, using advanced algorithms to better automate the thermal pulses, among other things. Other Wristify co-inventors from MIT include sophomore Mike Gibson and graduate students Matt Smith and David Cohen-Tanugi.

MECHANICAL ENGINEERING RESEARCH & NEWS UPDATE (Oct. 10, 2013)

Yesterday Nobel prize in chemistry has also been awarded but do you know Chemistry Nobel Goes to Work that Could Help Make Cars More Efficient?

Nobel Prize for Chemistry celebrates detailed simulations of combustion. This year’s Nobel Prize in Chemistry goes to three researchers who developed powerful computer models that have been used, among other things, to model combustion.

Computer models have become essential to improving the efficiency and emissions of internal combustion engines, gas turbines, and other equipment that depends on combustion. For example, they allow researchers to make subtle changes to the shape of pistons to ensure that fuel and air mix properly and burn cleanly, and at just the right rate. Or to understand how it’s possible to enhance efficiency by burning more than one fuel (as “Exploding Engine Could
Reduce Fuel Consumption”).

The awardees are Martin Karplus, of Université de Strasbourg and Harvard University, Michael Levitt from Stanford University, and Arieh Warshel from the University of Southern California.

LATEST MECHANICAL ENGINEERING RESEARCH UPDATE (Oct. 2, 2013)

Discovery of Charged Droplets Could Lead to More Efficient Power Plants:

— In a completely unexpected
finding, MIT researchers have discovered that
tiny water droplets that form on a
superhydrophobic surface, and then "jump" away
from that surface, carry an electric charge. The
finding could lead to more efficient power plants
and a new way of drawing power from the
atmosphere, they say.

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The finding is reported in a paper in the journal
Nature Communications written by MIT postdoc
Nenad Miljkovic, mechanical engineering
professor Evelyn Wang, and two others.
Miljkovic says this was an extension of previous
work by the MIT team. That work showed that
under certain conditions, rather than simply
sliding down and separating from a surface due
to gravity, droplets can actually leap away from
it. This occurs when droplets of water condense
onto a metal surface with a specific kind of
superhydrophobic coating and at least two of the
droplets coalesce: They can then spontaneously
jump from the surface, as a result of a release of
excess surface energy.
In the new work, "We found that when these
droplets jump, through analysis of high-speed
video, we saw that they repel one another
midflight," Miljkovic says. "Previous studies have
shown no such effect. When we first saw that, we
were intrigued."
In order to understand the reason for the
repulsion between jumping droplets after they
leave the surface, the researchers performed a
series of experiments using a charged electrode.
Sure enough, when the electrode had a positive
charge, droplets were repelled by it as well as by
each other; when it had a negative charge, the
droplets were drawn toward it. This established
that the effect was caused by a net positive
electrical charge forming on the droplets as they
jumped away from the surface.
The charging process takes place because as
droplets form on a surface, Miljkovic says, they
naturally form an electric double layer -- a layer
of paired positive and negative charges -- on
their surfaces. When neighboring drops coalesce,
which leads to their jumping from the surface,
that process happens "so fast that the charge
separates," he says. "It leaves a bit of charge on
the droplet, and the rest on the surface."
The initial finding that droplets could jump from
a condenser surface -- a component at the heart
of most of the world's electricity-generating
power plants -- provided a mechanism for
enhancing the efficiency of heat transfer on
those condensers, and thus improving power
plants' overall efficiency. The new finding now
provides a way of enhancing that efficiency even
more: By applying the appropriate charge to a
nearby metal plate, jumping droplets can be
pulled away from the surface, reducing the
likelihood of their being pushed back onto the
condenser either by gravity or by the drag
created by the flow of the surrounding vapor
toward the surface, Miljkovic says.
"Now we can use an external electric field to
mitigate" any tendency of the droplets to return
to the condenser, "and enhance the heat
transfer," he says.
But the finding also suggests another possible
new application, Miljkovic says: By placing two
parallel metal plates out in the open, with "one
surface that has droplets jumping, and another
that collects them … you could generate some
power" just from condensation from the ambient
air. All that would be needed is a way of keeping
the condenser surface cool, such as water from a
nearby lake or river. "You just need a cold
surface in a moist environment," he says. "We're
working on demonstrating this concept."
The research team also included graduate
student Daniel Preston and Ryan Enright, who
was a postdoc at MIT and the University of
Limerick and is now at Bell Labs Ireland, part of
Alcatel-Lucent. The work received funding from
the U.S. Department of Energy through the MIT
Solid-State Solar-Thermal Energy Conversion
Center, the Office of Naval Research and the
National Science Foundation.

Latest Mechanical Engineering Research Update (September 29, 2013)

Nanosteel Targets The Auto Industry:

According to a 2012 report by The Fredonia Group, the worldwide demand for nanomaterials is expected to rise 250% to $5.5 billion in 2016. With steel being one of the most common materials in the world with more than 1.3 billion tons produced annually, there is a significant opportunity to improve upon its performance through the use of nanotechnology.
Steel has a crystalline structure and the smaller the crystals dictate the strength of steel. The problem with using smaller crystals in steel is that the material becomes more brittle. One company that has solved this problem is Nanosteel. 

 

One of the problems automakers face is how to development new materials that will reduce the weight of the automobile to meet the challenge of higher fuel economy standards without compromising safety. Advanced High Strength Steels (AHSS) are the fastest growing material in today’s automotive industry with an availability target of 2017-2025 for integration into vehicle structural designs and production. NanoSteel has designed a new class of AHSS sheet materials with nano-scale microstructures which can handle high loads but retain the ability to be shaped and formed at room temperature into automotive parts. Last month "Nanotechnlogy" company released the results of a study performed by EDAG, Inc ., a globally-recognized independent engineering firm. In this study it was shown that company’s Advanced High Strength Steel (AHSS) enabled a 30% reduction of weight in the Body-In White structure of a 2011 Honda Accord while meeting North American performance and safety targets.