CHARACTERISATION OF INTER-LAMINAR SHEAR STRENGTH (ILSS) OF A RESIN INFUSED WIND TURBINE BLADE POLYMER COMPOSITE VIA THE SHORT BEAM SHEAR TEST

Resin infusion process is the most preferred process by manufacturer to fubricate
composite wind turbine blade. The application of this process affects the mechanical
property of composite wind turbine blade such as interlaminar shear strength (ILSS).
However the ILSS distribution for composite wind turbine blade that has unsymmetrical
shape is not widely known and it needs to be quantified in order to measure the quality
of the blade. The purpose of this study is to characterise the ILSS of a resin infused wind
turbine blade polymer composite via short beam shear test and the map its distribution in
a single blade. A composite wind turbine blade was manufactured by using resin
infusion process and the resin infused in line feed from root to tip direction. The
composite blade was divided into 27 blocks with 9 columns and 3 lines and a total of 6
specimens per block were cut according to ASTM Standard 02344. Universal testing
machine with three point bending fixture used for the short beam shear test and the
maximum load observed during test is converted into ILSS value by using ILSS
equation obtained from ASTM Standard 02344. It was found that the root area of the
blade has the highest ILSS followed by its middle area and root area. Moreover, the
lower side of the blade has higher ILSS value compared to its upper side. The results
showed that the specimen obtained from area containing low void formation has high
ILSS value while area containing high void formation leads to low ILSS value. The void
rormation in the composite wind turbine blade influences tits ILSS distribution. As the
ILSS mapping objective was achieved, the ILSS value variation among specimens
obtained from the upper side of the blade is higher compared to its lower side. It proved
that the ILSS value at the lower side of the blade is more consistent compared to its
upper side. Several recommendations also have been discussed in this report in order to
improve the methodology process and to obtain more accurate data.