CubeSat Smart Frame

This is my first entry for the GrabCAD Challenge: https://grabcad.com/challenges/the-cubesat-challenge While setting a task, four major conflicting requirements to the structure of the CubeSat were found: 1) Requirements for vibration resistance demand high level of stiffness; 2) High temperature stability of the frame that is close to aluminium; 3) The highest possible ratio of inner (usable) volume to the volume of the frame (based on the design PC104 of modules installed inside); 4) Availability of material. All commercially available plastic materials have at least twice the coefficient of linear expansion compared with aluminium. The expansion of the plastic frame from PEI in heating at 100 degrees in 1 unit, may be over 0,5 mm that is unacceptable. Exotic materials – carbon or glass fiber PEKK or metals are so far either commercially unavailable for SLS technologies or too experience, so they were excluded from the list of preferred materials as those materials close to unobtainium. Moreover, the existing technology of DMLS has significant limitations in size of a future part. In this case the frame design MUST comply with all the above mentioned requirements. If at least one demand is not met the project will lose its meaning! Additional desired requirements: 1) Effective thermal conductivity from inner parts of the skin; 2) Minimization of the number of parts; 3) Workability; 4) Affordability; After painful consideration of various options, the following solution was found. The idea is not new; a similar principle has been used in ordinary wooden barrels for many centuries. As a rule, the inner parts of the satellite consist of several modules of PC104 format fixed together with standoffs. This assembly is precision and makes up a fairly firm construction by itself. Printed circuit boards are made of fiberglass that is temperature stable on the axis X and Y (slightly better than aluminum). On top of that, the technology of manufacturing of PCBs (as a rule, C