2022
CRYOGENIC TENSILE TEST FIXTURE LOUIS FORMAN, THOMAS GIBSON, KEVIN SIKES, DANIEL CABRERA
Material properties change at low temperatures, and tensile testers that can achieve these temperatures are large and expensive. Our goal is to create a cryogenic tensile tester that is low-scale and low-cost.
Requirements: • Operate at temperatures ranging from 100K to 300K (-280°F to 80°F) • Build a testing fixture to withstand 10,000 lbs of force
Completed Tensile Test Fixture
System Overview and Background
Introduction
Subsystems: • Mechanical Frame – Refurbished 1970’s Instron Tensile Tester, includes motor and gearbox. • Cooling System – Includes liquid nitrogen delivery and conduction-cooling system, and foam chamber for insulation. • Sensors and System Control - Includes an extensometer, load cell, rotary encoder and a K-type thermocouple.
Control Diagram
• Perform, monitor and collect tensile test data, including force, strain, displacement and temperature
Design Validation
• Accommodate for 3 inches of travel of elongation of sample
Finite Element Analysis
Liquid Nitrogen Testing Specimen Temperature
• Total budget of $6581
Thermocouple Ave. (C) 40 20
1 2
3
• Relays are used to control the clutches and the motor. • Clutch 3 acts as an emergency brake. • Emergency stop button will de-energize the motor and engage clutch 3 after the button is pressed down and until it is reset.
Data Collection
Force lb
2) Liquid nitrogen flows into two metal cups, one above the test specimen and one below. 3) Test specimen is then cooled through conduction to desired temperature.
• Load cell force still needs to be properly scaled • The test was paused in the middle which caused the dip in force and constant elongation section
-60 -80 -100 -140 -160
Time (hr:min:s)
The chamber was simulated Liquid nitrogen in SolidWorks to provide a testing cooled the specimen factor of safety of >3. down to -141°F (~129 K).
Future Work •
Time
-40
-120
Load Cell
1) Liquid nitrogen is poured into copper tubes through inlets at top of cooling chamber.
-20
0:00:00 0:01:40 0:03:20 0:05:00 0:06:40 0:08:20 0:10:00 0:11:40 0:13:20 0:15:00 0:16:40 0:18:20 0:20:00 0:21:40 0:23:20 0:25:00 0:26:40 0:28:20 0:30:00 0:31:40 0:33:20 0:35:00 0:36:40 0:38:20 0:40:00 0:41:40 0:43:20 0:45:00 0:46:40 0:48:20 0:50:00 0:51:40 0:53:20 0:55:00
Cooling System
Temperature (°F)
0
Integrate more speed options into the machine using a variable frequency drive
• Improve Cooling System to achieve more consistent low temperatures
We would like to acknowledge Dr. Michael Maughan, Dr. Matthew Swenson, NASA Idaho Space Grant Consortium, Bill Magnie, Jared Gray and Abdallah Smadi for their contributions to this project.
The Ice Breakers