Chapter 41. Fiber Twist Test: A New Single Fiber Test Method to Measure Composite Interface Properties

  1. John B. Wachtman Jr
  1. Turgay Erturk and
  2. William M. Chepolis

Published Online: 26 MAR 2008

DOI: 10.1002/9780470314715.ch41

Proceedings of the 19th Annual Conference on Composites, Advanced Ceramics, Materials, and Structures - A: Ceramic Engineering and Science Proceedings, Volume 16, Issue 4

Proceedings of the 19th Annual Conference on Composites, Advanced Ceramics, Materials, and Structures - A: Ceramic Engineering and Science Proceedings, Volume 16, Issue 4

How to Cite

Erturk, T. and Chepolis, W. M. (1995) Fiber Twist Test: A New Single Fiber Test Method to Measure Composite Interface Properties, in Proceedings of the 19th Annual Conference on Composites, Advanced Ceramics, Materials, and Structures - A: Ceramic Engineering and Science Proceedings, Volume 16, Issue 4 (ed J. B. Wachtman), John Wiley & Sons, Inc., Hoboken, NJ, USA. doi: 10.1002/9780470314715.ch41

Author Information

  1. University of Massachusetts Lowell, Lowell MA 01854

Publication History

  1. Published Online: 26 MAR 2008
  2. Published Print: 1 JAN 1995

ISBN Information

Print ISBN: 9780470375372

Online ISBN: 9780470314715

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Keywords:

  • expansion;
  • contraction;
  • friction;
  • tolerance;
  • intrinsic

Summary

A new single fiber test technique to measure interface properties in continuous fiber composites has been developed. The Fiber Twist Test (FTT) has advantages over fiber pullout, pushout and other axially loaded tests. These include the absence of lateral Poisson's expansion or contraction, and maintenance of a constant embedded fiber length during friction measurements. The former leads to a linear variation of stresses and nearly pure mode III loading of the interface. These should assist more direct measurement of interfacial properties. However, FTT in some tests is found to be somewhat insensitive in detecting the torque build up and drop associated with interface debonding. The interface shear stress singularity in FTT at the entrance of the fiber to the matrix is approximately 30% higher than the interface stress in axially loaded tests [1]. This may suggest a lower sensitivity of FTT to detect debond torque drop, Otherwise, it seems that FTT is a viable test technique to measure composite interface properties more directly than the axially loaded tests.