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This is a collective page to informally document what we learn from preliminary research.

General guidelines:

What type of device (more specific than just “thermocouple”)?
What grade of device (on a range from hobby/DIY - industrial grade)
How do we use the device (power, signal connections, press a button, etc.)

How/where do we mount the device (epoxy, thermal tape, paste, frame, etc.)
What can go wrong with mounting and ways around it

EX: routing thermocouples in nose cone requires for wire to run into the airframe to reach the DAQ system, jeopardizing deployment of the nose cone
Potential solutions: use special wires that break during deployment, embed copper contacts into the airframe/nose cone shoulder

Based on the info collected above, what are the common price ranges?
Can you list some potential sensor candidates or suppliers? If so, please do.

Assignments:

Thermal - Eric & Juan

Vibration - Yasu

Chute/Airframe loads - Joanna & Jay

Flutter - Yasu

Thermal (Eric + Juan)

Omega's 5 Points:

HOW TO CHOOSE A THERMOCOUPLE

1. Determine the application where the thermocouple will be used

2. Analyze the temperature ranges the thermocouple will be exposed to

Max 800 K (980 F) --> Type J, E suit this max (J: 32 - 1400 F, E: -328 - 1600)

3. Consider any chemical resistance needed for the thermocouple or sheath material

4. Evaluate the need of abrasion and vibration resistance

5. List any installation requirements

Coltronic 4700 thermal epoxy

Sheath Considerations (for sheated thermocouples)

Grounded vs Ungrounded --> We want grounded (probe wires are physically attached to the wall of the sheath) to maximize thermal contact, no concern for electrical isolation

Other Notes:

https://www.epj-conferences.org/articles/epjconf/pdf/2017/12/epjconf_efm2017_02075.pdf

Calibration is key
Temperature Calibration Uncertainty detailed in Guide to exp. Of Uncertainty in Measurement
“Intrinsic Thermocouples” might give us better spatial resolution (microtips)

https://www.epj-conferences.org/articles/epjconf/pdf/2017/12/epjconf_efm2017_02075.pdf

Seebeck effect
G,C,D are for high temp, K for VERY high temp

NiCr-NiAl used in experiment is oxidation proof, resistant to higher temps, reducing atmosphere, and sulphur compounds

“The thermocouple-based method has some limitations. One of the major problems is attaching a thermocouple to the surface to be measured. Incorrect bonding may cause the device to show a temperature lower than the actual one. When a thermocouple is used to measure the temperature of an element in a high frequency radio circuit, it may change the electrical characteristics of that circuit. A thermocouple fixed to a small electronic element may be responsible for the removal of heat from the element. As a result, the temperature displayed is lower than the actual temperature, i.e. one measured before the thermocouple was attached. Decalibration may lead to an error in measurement; it may change the electrical characteristics, which will make the reading inaccurate. Finally, an open thermocouple junction may also cause errors in temperature measurement [19]. "

Possibly add IR Thermal camera for data fusion

Vibration (Yasu)

http://www.ni.com/white-paper/3807/en/

ceramic piezoelectric sensor/ accelerometer
single axis / triaxial accelerometer
Engineer’s guide to accurate sensor measurements: http://download.ni.com/evaluation/daq/25188_Sensor_WhitePaper_IA.pdf
what’s the effect of the constant acceleration/deceleration of the rocket on the sensors?
triaxial, +-500g, 2~7000Hz model(356B21): $1,125

figure: overview of triaxial accelerometers from NI (from white paper)

figure: dimensions of 356B21 accelerometer(from its product drawing, units in inches)

https://www.popsci.com/how-little-vibrations-break-big-rockets interesting article on the effect of vibration on rockets (but liquid-fueled rockets, so shouldn’t be a concern for us)
http://www.eng.hmc.edu/NewE80/PDFs/VibrationLec2013.pdf

causes of vibration:

thrust oscillation
noise(pressure waves) from motor
explosive bolts
fluid flow phenomena

vibration mode of rocket
https://link.springer.com/chapter/10.1007/978-3-642-67208-8_34 Shock and Vibration Characteristic of Solid Rocket Vehicles

1979 paper from Japan
piezo vibration meters, flat response up to 2kHz

Falcon 9 User's Guide - SpaceXhttps://www.spacex.com/sites/spacex/files/falcon_9_users_guide_rev_2.0.pdf Falcon 9 User’s Guide

(for SpaceX customers)
shock loads during flight:(p.26)

release of launch vehicle hold-down at liftoff
stage separation
(fairing deployment, spacecraft separation)

2018/09/30

acceleration about 90m/s2(~9g) for 2012 rocket -> must consider range of accelerometer
ADXL377

±200g range
up to 1000Hz(z axis), 1300Hz(x,y axes)
“cross-axis compensation”: ±1.4%: how much perpendicular acceleration is coupled to signal (https://www.mouser.com/pdfdocs/an32_crossaxis_compensation.PDF)
sensitivity: 5.8~7.2mV/g -> 0.59~.73mV/(m/s2) (need calibration?)
Arduino’s analogRead() is 10 bits, so as a result 4.8mV/unit, 6.5~8.1(m/s2)/unit
$25

ADXL345

±16g, output resolution 13 bits
up to 3200Hz sampling
1/32 = 0.031g/bit = 0.3 (m/ss)/bit
$18

Chute (Jay + Joanna)

Load testing: http://www.futek.com/product.aspx?t=load

Need to know what kind of weight this thing needs to take: too much capacity implies too little precision

Upper bound 2000 lbs

Type of cell / how to install

https://sensor-con.en.alibaba.com/productgrouplist-803400380/Load_Cell.html?spm=a2700.icbuShop.0.0.120b4eb17iN3Gv cheap load cells from Shenzhen

These look like they’ll work, as long as we select a generous/correct mass range. Doesn’t look like we have a huge precision loss as the mass range increases.

From NASA Langley case file, they had problems with lead wire breakage- we should make sure we prepare for this problem

https://www.omega.com/prodinfo/strain-gauges.html

Pretty good website, introduces different types of strain gauges and gives recommendations
Karma strain gauges are good for use over wide temperature ranges
Around $50-60 from Omega

http://www.ni.com/white-paper/3642/en/