Characterisation of Voids in a Polymer Composite Wind Turbine Blade Manufactured via Resin Infusion Process

Resin infusion is an advanced laminating technique that greatly improves the quality and
strength of a material. During the resin infusion process, void may be formed due to in
proper degassing process, out gassing of dissolved gas in the resin, evaporation of
volatile component in the resin, shrinkage of resin and leakage in connection and mould.
Void is a formation of air bubbles trapped during a composite fabrication and it has a
strong impact on the mechanical properties. Therefore, void must be reduced by
controlling the parameters such as resin viscosity, vacuum pressure and cure
temperature. It is important to know the void content and how it has been distributed. In
this project, the void analysis was done to the wind turbine blade polymer composite that
manufactured using resin infusion process. The objective of the project is to characterize
the void in a polymer composite wind turbine blade manufactured via resin infusion
process and a mapping of void content will then be produced. The processes involved
are manufacturing the blade using the strategy design of line feed type from root to tip,
the specimen was cut from various important locations, separation of wood from the
fiber glass and lastly the void content testing. A total of I 08 specimens have been tested
using the loss on ignition method to measure the void content according to the ASTM
Standard 02584-94. In this method, the specimen is burned in a furnace until only the
reinforced material remains. Next, the void content calculated by referring to the ASTM
Standard 02734-94. It was found that the lower side (23.71%) has lesser void content
than the upper side (25.42%) and voids tend to accumulate at the outlet area (26.23%)
than the inlet area (23.36%). There are also variation distributions of the void through
the process for upper side and lower side due to the flow distribution. In the future, the
test should be done to other strategies design such as line feed type from tip to root to
find the best strategy design that can produce the lesser void content.