Composite Materials Research Progress

In: Composite Materials Research Progress ISBN: 1-60021-994-2
Editor: Lucas P. Durand, pp. 209-236 © 2008 Nova Science Publishers, Inc.
Chapter 6
RESEARCH DIRECTIONS IN THE FATIGUE TESTING
OF POLYMER COMPOSITES
W. Van Paepegem * , I. De Baere, E. Lamkanfi,
G. Luyckx and J. Degrieck
Dept. of Mechanical Construction and Production, Sint-Pietersnieuwstraat 41,
9000 Gent, Belgium
Abstract
For a long time, fatigue testing of composites was only focused on providing the S-N
fatigue life data. No efforts were made to gather additional data from the same test by using
more advanced instrumentation methods. The development of methods such as digital image
correlation (strain mapping) and optical fibre sensing allows for much better instrumentation,
combined with traditional equipment such as extensometers, thermocouples and resistance
measurement. In addition, validation with finite element simulations of the realistic boundary
conditions and loading conditions in the experimental set-up must maximize the generated
data from one single fatigue test.
This research paper presents a survey of the authors’ recent research activities on fatigue
in polymer composites. For almost ten years now, combined fatigue testing and modelling has
been done on glass and carbon polymer composites with different lay-ups and textile
architectures. This paper wants to prove that a synergetic approach between instrumented
testing, detailed damage inspection and advanced numerical modelling can provide an answer
to the major challenges that are still present in the research on fatigue of composites.
1. Introduction
The research on fatigue in composites in general has been largely inspired by the research on
fatigue in metals. Despite the advantages that this knowledge transfer has provided, it has also
brought about that there is still a widespread belief that the fatigue behaviour of metals and
composites is indeed very similar. As a consequence the aim of most fatigue tests on
* E-mail address: Wim.VanPaepegem@UGent.be