Zusammenfassung
Composite insulators are rapidly replacing their
porcelain counterparts in electrical substation applications.
These insulators consist of a glass-reinforced
polymer (GRP) rod, with two metal end fittings
radially crimped onto the ends of the rod during
assembly. In this paper, axisymmetric finite element
models are developed to evaluate the mechanical
performance of composite insulators under externally
applied axial compression. The analyses are performed
by assuming both a perfectly bonded interface between
the composite rod and the end fittings, and an imperfect
interface which permits large relative sliding with
Coulomb friction. Results indicate that the perfect
interface model is unrealistic since it predicts singular
stresses at the interface comer and an overall linear
structural response. On the other hand, the imperfect
interface model is found to simulate accurately the
structural non-linearity caused by relative sliding of the
GRP rod within the end fittings. The imperfect interface
model has therefore been used to evaluate the effects of
interface friction, and the extent of crimping, on the
maximum load-bearing capacity of substation composite
insulators.
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