June 17: Compression Test to Verify Presence of Y-Fitting "Stiction"

• Configuration:

  • ACS: Fully Assembled; OFF for this Test to Eliminate Thermal Effects
  • Mounting: In TBF/Diamond
  • Cooling: Chillers
  • Optical Source: None (ACS Off)
  • Starting Temp: Ambient throughout Test (ACS Off)
  • Add'l Sensors: LVDTs to Monitor Motion of Bench Relative to Enclosure & Theodolites to Monitor TBF and ACS Optical Cube Motion

• Figures:

  • LVDT setup: ( HTML )
  • LVDT data: ( PDF )

• Results:

  • TBF B-Latch Used to Compress Enclosure from 0 to 800lb in 50lb Increments
    • Increasing Load Compresses Both Enclosure & Optical Bench by ~25 mil
    • ACS Optical Cubes' Motion of ~6 to 18 as Indicates Bench is Bending w/Increasing Load

• Conclusion:

  • Optical Bench Moves with Enclosure
  • Y-Fitting is not Behaving per Design