Classic "U-shaped" Carbon Thermal Strap Assembly undergoing a Thermal Conductance Test
Our sister company also provides the world's only flexible graphite (carbon) fiber thermal strap. TAI, Inc. works closely with TechApps in order to further develop innovations in the field of carbon fiber thermal strap technology.
At TAI, Inc., we use various government contracting vehicles including the SBIR program, in order to develop new carbon fiber thermal management technologies, and we look forward to working on our first SBIR ph I program in 2016.
Carbon fiber thermal strap technology is ideal for space applications that require very low mass, yet have high thermal conductance and/or vibration damping requirements. The average GFTS assembly typically weighs just 1/4 - 1/10 the mass of a comparable metallic foil or rope thermal strap, yet they provide roughly the same thermal performance.
It is important to understand that though the material conductance of graphite/carbon fiber rope is much higher than that of aluminum or copper, because carbon fiber ropes are not packaged as densely as these other materials, the average strap will offer (roughly) the same thermal performance as a copper strap.
Graphite Thermal Strap Materials
Carbon thermal strap assemblies use GraFlex bundles (made from graphite fiber with thermal conductivity >800 W/m-K). Each bundle consists of thousands of carbon fibers wrapped with a unique polyester cord. These fibers have 2.75x the thermal conductivity of copper at room temperature and one quarter of the density. As such, on a thermal conductivity/mass basis, they are 11x more weight efficient than copper, and over 6x more weight efficient than aluminum.
Terminal blocks are made using a variety of materials, though aluminum is the most common choice due to it's low mass.
Testing and Analysis
TAI Inc. will offer some testing services starting late 2016, in addition to the testing options offered by our sister company. In a carbon thermal strap program, each strap will pass quality checks and undergo thermal conductance testing after construction to verify requirements compliance prior to delivery to the customer.
TechApps routinely produces flexible thermal links designed and fabricated to specific customer requirements that have less than a 2% variation in thermal conductance, so performance is both predictable and repeatable.
They also have the capability to test the stiffness in all linear axes, shock and vibe testing, and thermal cycling, should your program require these tests as well.
Graphite Thermal Strap Space Qualification Test Data
These innovative thermal strap assemblies have undergone extensive testing and qualification under severe environmental and launch conditions. If your program requires stiffness, shock, vibe or other types of qualification testing, let our partners at TechApps know, and they will work with you to develop your SOW and spec accordingly. The table below illustrates extremes which carbon thermal straps have been tested to in previous space flight programs.
TechnApps has provided graphite thermal straps to aerospace organizations across the globe; from NASA, to the ESA and JAXA, and many prime contractors like LMCO, Ball and Airbus.