Aerospace Hinges that Morph
Though the exact origin of hinges remains unclear, we do know that hinges have been used as early as 5000 BC. The evolution of hinges is nothing short of astounding when one considers every corner of today’s world quite literally relies on the vast array of hinges to meet the functional needs of countless applications ranging from engineering to home construction, to transportation to space travel.
And when it comes to space travel in particular, things become really interesting as far as hinges are concerned. Hinges for outer-space applications are designed to combat out-of-this-world demands that involve thermal expansion, galling, cold welding and lubrication in a vacuum environment. Highly-specialized hinges that successfully meet these needs are, also, self-actuating, self-guiding and self-locking. Zero-gravity hinges must have the ability to enable solar panels to open at predetermined angles and configurations as well as permit antennas to deploy at just the right time. But what if you were told that hinges designed for outer-space can actually morph from one ‘form’ into another?
The adage, “Truth is stranger than fiction” could apply, here – meet Elastic Shape-Memory Composite Hinges.
Elastic Shape-Memory Composite Hinges
Elastic Shape-Memory Composite Hinges, or EMCH, are meticulously engineered to move any attached mass on a spacecraft. These unique hinges are used for in-space deployment of antennas, reflectors, cameras, solar panels, sun shields, and more. Unlike their earthly-counterpart hinges, EMCH are not only lighter, but they are much stronger; and it goes far beyond that! To begin with, EMCH are created from a high-performance fiber (this is where it gets interesting) and a shape-memory polymer resin. When the resin is heated above a select temperature (technically known as glass transition temperature), the composition of the EMCH becomes flexible and can be folded, or packed. To maintain the folded state of the hinge, the resin is cooled below the glass transition temperature. Then, when a space component is ready to be deployed or launched from a spacecraft or satellite, the EMCH’s shape-memory resin is reheated to above the glass-transition temperature, allowing the resin to return to its as-fabricated shape.
EMCH – Transformable, Conductive and Multi-Functional
One would logically think this type of hinge would lose a good portion of its original shape with these types of extreme procedures; but shape deformation after heating, cooling and re-heating is virtually non-existent – the EMCH maintains higher than 99.999% shape recovery! Astoundingly, the hinge regains its original shape in not minutes, but mere seconds!
Some types of shape-memory hinges are embedded with switch-control heaters, allowing the hinge to bend and alter its shape when heated. Though shape-memory hinges are currently in use for very sophisticated aerospace applications, prototypes for the US government, medical and automotive industries, and other commercial applications are being intensely researched.
Shape-memory hinges are also designed to be conductive, giving them the ability to route power through multiple solar-cell panels. The panels are interconnected by the conductive hinges that permit the deployment of arrays of solar cells. And to top it off, multi-functional shape-memory hinges can serve as latches that lock the solar panels into place!
Engineers from MIT and Singapore University of Technology are feverishly investigating small structures – some as little as 1-inch in height – that can revert back to 100% of their original shapes after those shapes have been stretched, twisted and bent at extreme angles. Online Journal Scientific Reports goes into more detail concerning shape memory materials. But when it comes to hinges that can ‘morph’ while in the farthest reaches of space, it makes one ask: What in the world will the next few decades bring?