Automated Bending Fatigue Tester by hedongchenchen


									Automated Bending Fatigue Tester

                Joel Knibbe
               Dale Slotman
              Eric Vander Zee
 The goal for this project is to design,
 build, and test an automated bending
 fatigue tester, for the Padnos School of
Project Requirements
 Test ¼” round stock
 Test specimens with strengths ranging from
  soft brass to steel.
 Apparatus must mate with the existing Instron
  Tensile Tester.
 Specimen must be in 4-point bending.
 Bar stock must be rotated to produce fully
  reversed bending scenario.
 Apparatus must count the number of
  revolutions to failure, and stop at failure
Four Point Bending

• Simply supported from below
• Simply loaded from above
Shear Diagram
Moment Diagram
Selected Concept
   1” square tubing (1/8”

   1” square stock

   1.25” round stock

   Self-aligning rod end
    spherical bearings
Testing Procedure
   Grind a flat on one end of the test specimen
   Insert test specimen through the bearings and the
    universal joint and secure with the setscrew
   Adjust the motor height to minimize the angular
    deflection of the universal joint
   Start and run the fatigue tester method, “fatigue”
    with the desired load
   Once the full load is applied gradually turn the
    speed control knob to the desired speed
   When the specimen fails, the tensile tester will
    stop and the motor should be stopped
Test Demonstration

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