Power Supply Unit

Challenge

Avionics systems mounted on spacecraft must operate in conditions of extreme heat, shock, noise and vibration for an extended period of time. Survivability of these avionics systems must be verified for events such as launch, stage separation, pressurization as well as orbital thermal gradients.

explodeSolution

Perform Advanced Analysis

Quartus was contracted by Boeing to perform analysis for the satellite electronics power supply unit shown below. Random vibration, shock, thermal, pressurization and fatigue analysis was performed.

Mitigate Impact Damage

Initial analysis showed the power supply met design requirements with positive margin, however, concern regarding shock damage to ribbon bonds prompted further analysis. Ribbon bonds are used in several locations in the model, with the highest level shock stress occurring in the FET-to-PWB ribbons. Stress exceeded yield for these gold ribbons, however, it was not known if they failed.

Design for Shock Loads

To accurately assess the shock damage to the FET-to-PWB ribbons, a breakout model was built and non-linear solutions were run with responses from the full model used as inputs to the breakout model. It was determined from the non-linear analysis that the FET ribbons yielded, but did not fail. The FET model with ribbon bonds as well as the breakout ribbon model are shown above.

stress_pics

Result

Quartus performed advanced analysis to verify survivability of avionics systems dumring launch. Full documentation of analysis results was delivered to Boeing for inclusion in a system level design review report.

Engineering Methods

  • Static Analysis
  • Modal Analysis
  • Random Vibration
  • Electronic Fatigue Analysis
  • Super-element Analysis

Computer Aided Tools

  • Pro-Engineer™
  • NX I-Deas™
  • NX NASTRAN™