TITLE:
Electrical Resistance Change of Carbon/Epoxy Composite Laminates under Cyclic Loading under Damage Initiation Limit
AUTHORS:
Akira Todoroki, Daichi Haruyama, Yoshihiro Mizutani, Yoshiro Suzuki, Tesuo Yasuoka
KEYWORDS:
Carbon Fiber; Electrical Properties; Non-Destructive Testing; Smart Materials
JOURNAL NAME:
Open Journal of Composite Materials,
Vol.4 No.1,
January
15,
2014
ABSTRACT: Self-sensing
multifunctional composite has sensing function using electrical resistance
changes. Carbon Fiber Reinforced Polymer (CFRP) composite is one of the
self-sensing multifunctional composites. For the reliability of the
self-sensing, electrical contact between the lead wire and the carbon fibers is
the most important issue. The present study focuses on the effect of the cyclic
loading of lower applied strain range than the fatigue damage level. As a
result, the electrical contact resistance at the copper electrode increased
with the increase of cycles. That means that the electrical change at the electrodes must be considered for the
long-term self-sensing monitoring system. When a four-probe method is used to
measure the electrical resistance, the contact resistance effect is minimized.
Moreover, angle-ply laminates have plastic
deformation caused by shear loading, and that causes electrical resistance
decrease during the cyclic loading. Cross-ply laminates of CFRP composites have no electrical resistance increase without damage.
Quasi-isotropic laminates of CFRP composites, however, have electrical resistance decrease with the increase of the
number of cycles because of the plastic deformation of the angle-ply laminates.