Postprint version. Published in Advanced Cement Based Materials, Volume 3, Issue 2, March 1, 1996, pages 54-71. Copyright © 1996 Published by Elsevier Science Ltd. All rights reserved. The definitive version can be found online at http://dx.doi.org/10.1016/S1065-7355(96)90072-3.
NOTE: At the time of publication, the author Daniel Jansen was not yet affiliated with Cal Poly.
Closed-loop testing systems provide the ability to directly control the deformation of the loaded specimen. This considerably enhances the precision, stability, and scope of the experiments. Closed-loop machines can be used to determine the stable response of test specimen or structure by monitoring and controlling the physical quantities that are sensitive to its behavior. The importance of the various components of the closed-loop controlled system and the test configuration is reviewed in the paper. The most critical aspect of designing the test is the choice of the controlled variable. With appropriate controlled variables and good system performance, several interesting and intricate testing techniques can be developed, as seen in the examples presented here.
Civil and Environmental Engineering