Cryo test of Sensor Wire Performance

DESCRIPTION

Although sensor wire specifications indicate performance at -60 deg C, it is necessary to the success of the mission to confirm through cryo chamber testing.

An example of the sensor wire that will be used for SpeedBall flights can be found at http://www.awcwire.com/Part.aspx?code=770L30H16J8.

Part Number E-30-7
AWG Size 30
Conductor Stranding 7/38
Nom. O.D. (in) 0.032
Nom. Insul. Thick. (in) 0.010
Approx LBS/MFT 1
Mil-Spec # M16878/4BBB
UL Style 1213
Mil-Spec M16878/4
Min. Temp -60°C
Max. Temp 200°C
Cond. Material Silver-Coated Copper
Insul. Material Polytetrafluoroethylene (PTFE)
NEMA Type HP3 Type E
NEMA# HP3-EXBBB

OBJECTIVE

  1. Determine effect of sustained -60 deg C temperature on flexibility of sensor wire.
  2. Determine effect of sustained -60 deg C temperature on wire bending fatigue failure.

EQUIPMENT

  1. outfitted cryo chamber, including
    1. styrofoam dry ice reservoir
    2. mounted fan
    3. temperature sensor
    4. web portal that displays temperature readings
    5. 10 lbs dry ice (if there is not enough left in the styrofoam dry ice chamber to complete the experiment)
  2. dry ice handling gloves
  3. sensor wire 36” in length
  4. flat table at least 30” in height
  5. clamp that is securely fastened to the flat table

PROCEDURE FOR OBJECTIVE 1

  1. Measure and record the flexibility of the sensor wire prior to cooling using a modified version of the Calmont Flexibility Test
    1. Hang 15” of the cable off the side of the table (21” on the table)
    2. 6” from the top of the table measure the distance from the table to the cable
    3. 12” from the top of the table measure the distance from the table to the cable
    4. Take the average of the two measurements = “flex value”
  2. Add dry ice into reservoir, if necessary. Be sure to wear the dry ice handling gloves.
  3. Place the same piece of sensor wire that was measured into the cryo chamber cooled at -60 deg C
  4. Wait 72 hours.
  5. Retrieve sensor wire from the cryo chamber
  6. Measure and record the flexibility of the sensor wire immediately by repeating the steps in 1.I-IV.

PROCEDURE FOR OBJECTIVE 2

  1. Measure and record bend fatigue failure of the sensor wire prior to cooling
    1. Clamp one end of the sensor wire so that it will remain fixed
    2. Bend the wire 90 deg in one direction and then 90 deg the other direction
    3. Repeat step 1.II 20 times.
    4. If the wire fractures before then, record the number of bends it took for the wire to fail; Else, record that the you failed to reach the wire's bend fatigue failure point
  2. Add dry ice into reservoir, if necessary. Be sure to wear the dry ice handling gloves.
  3. Place the same piece of sensor wire that was measured into the cryo chamber cooled at -60 deg C
  4. Wait 72 hours.
  5. Retrieve sensor wire from the cryo chamber
  6. Measure and record bend fatigue failure of the sensor wire immediately by repeating the steps in 1.I-IV.
testing/cryogenic/compmat/cryo15.txt · Last modified: 2010/10/26 02:35 (external edit)
 
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