Tiny Machines: Mini 'Dragonfly,' Microvalve Win Big in Student Contest
Winner in Novel Design Category by Texas Tech University.
CREDIT: Sandia National Laboratories
Competitors in the annual micro machine contest at Sandia National Laboratories must think small, but they also must think complexly. This year, a tiny mechanical dragonfly the size of a dust mote and a sensitive microvalve design combined intricacy and small scale enough to impress engineering experts and walk away with the win.
These vanguards in the new wave of the world's tiniest devices claimed top prizes at a student engineering competition held at Sandia National Laboratories in Albuquerque, N.M. The microvalve emerged as the brainchild of a Carnegie Mellon University team, while the incredible dragonfly design was the creation of Texas Tech University students.
"Among the countless insect species able to fly, we chose the dragonfly because it flaps its wings in the vertical direction, rather than back-and-forth or in a rotary motion," said Sahil Oak, a Texas Tech student. "The vertical motion of the large wings in our design not only provides greater surface area for lift than most flying insects, but the wings cool faster, enabling faster flapping."
The insect-inspired device has wings just 0.5 millimeters long about the width of five human hairs and 0.1 millimeters wide. Small intermittent electric currents make the wings flap by creating heat expansion and contraction, and the student engineers used the wing material's response to create the most aerodynamic strokes possible.
Such mechanical dragonflies could herald future drones capable of sneaky aerial surveillance over battlefields and zipping into danger zones too hazardous for squishy humans.
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The tiny microvalve created by Carnegie Mellon University students also received a prize in the educational category. The microelectromechanical system (MEMS) uses a switch-based design similar to the ball-and-flapper valves found in most toilets or those found in artificial heart valves, so that it has very fine control over tiny amounts of liquid.
"One of the most common types of microvalve is electrostatically operated, which is the model for our design," said Vitali Brand, leader of the Carnegie Mellon team.
"The best microvalves are useful in certain fuel cell designs and in microengines because they can close or open in less than one-thousandth of a second and function against heavy pressures without leaking."
The microvalve design only requires millionths of a Joule of energy to switch its state (1 watt is equivalent to 1 Joule per second). Such microvalves could help future medical devices analyze a patient's medical state by controlling and redirecting tiny amounts of blood or other fluid samples.
Student teams first had to come up with ideas, create computer models of the designs and then analyze the results. They then submitted their results to the contest, which is open to institutional members of the Sandia-led MEMS University Alliance program. Sandia's engineering experts and university professors looked over the designs to pick the winners.
Now Sandia's state-of-the-art MESA fabrication facility will create actual micro machine parts out of polysilicon based on the student designs. The parts will be shipped back to university students so that they can run final product comparisons with their computer simulations.