Title :
An Optical Method for Strain-Controlled Fatigue Testing of Microspecimens
Author :
Kim, Chung-Youb ; Sharpe, William N., Jr. ; Hemker, Kevin J.
Author_Institution :
Div. of Mech. & Automotive Eng., Chonnam Nat. Univ., Chonnam, South Korea
Abstract :
This letter presents an initial version of an optical method for measuring and controlling strain over very short gauge lengths. Reflective indentations which are 200 μm apart are put in a steel microspecimen which is 3 mm long. When illuminated with a laser, interference fringes are produced; their motion is monitored with photomultiplier tubes. A computer system converts fringe motion to strain and controls the test. The specimen preparation and measurement system is described, and the control of peak cyclic strain at 1140 ± 10 μstrain is demonstrated.
Keywords :
fatigue testing; indentation; interferometry; photomultipliers; reflection; steel; strain measurement; distance 200 mum; fringe motion; gauge length; interference fringes; laser illumination; measurement system; optical method; peak cyclic strain control; photomultiplier tubes; reflective indentations; size 3 mm; steel microspecimen; strain measurement; strain-controlled fatigue testing; Fatigue; Laser beams; Measurement by laser beam; Optical interferometry; Optical variables measurement; Strain; Strain measurement; Fatigue; optical interferometry; strain control; strain measurement;
Journal_Title :
Microelectromechanical Systems, Journal of
DOI :
10.1109/JMEMS.2012.2190976
