Experimental characterization of thermal shims for space applications

MDA Montreal possesses a niche expertise on a wide variety of high-performance satellite telecommunication antennas. These antennas are exposed to extremely harsh environments. Some panels require a rigid mechanical assembly (i.e., nut and bolt fastening) but must preserve their thermal isolation for the proper operation of the antennas and to limit heat exchange towards the spacecraft. Relatively thick thermal shims or washers are currently inserted into these assemblies to almost completely block the heat flow between the two structures. The main problem is due to the viscoelastic behaviour of the current shim material used. Under a compressive initial load, the shims exhibit an important stress relaxation (i.e., softening of the material with respect to time) and the initial pre-load in the fastened assembly is significantly reduced over time. The main objective of this internship perfomed by a post doctoral fellow is to resolve MDA stress relaxation problem by designing and predicting the response a high-performance multifunctional shim featuring an almost elastic mechanical behaviour while exhibiting a very low thermal conductivity and characterizing the stress relaxation behaviour of “standard” thermal washers materials.

Faculty Supervisor:

Drs. Daniel Therriault & Martin Lévesque

Student:

Thibaud Chatel

Partner:

MDA Corporation

Discipline:

Engineering - mechanical

Sector:

Information and communications technologies

University:

Polytechnique Montréal