  Efficient structural repair of wind turbine blades is essential to limiting
global warming and reducing the Levelized Cost of Energy (LCOE). Repairs
carried out up-tower are sensitive to environmental conditions whose effect on
the material properties during processing needs to be accounted for to
accurately predict the repair outcome. This study investigates the effect of
moisture content from environmental exposure on the cure kinetics of an
infusion resin system used in wind turbine blade manufacturing and repair and
provides an experimentally validated finite element tool for the analysis of
cure cycle repairs as a function of repair geometry and moisture content.
Moisture absorption tests on the two-part infusion system reported up to 12%
moisture uptake by the curing agent under high temperature and relative
humidity conditions. Differential scanning calorimetric measurements of resin
in the presence of moisture revealed an accelerated cure behavior. Numerical
predictions of a repair model agreed very well with the corresponding lab-scale
repair and revealed a substantial temperature lag within the repair patch which
resulted in thermal gradients and spatial distribution of the degree of cure.
It was shown that the repair geometry and the accelerated-cure kinetics greatly
influenced the temperature and cure distribution within the repair. The
proposed approach can be used to reduce turbine downtime by minimizing the
curing time.
