Piezoelectric smart composite blades for collision monitoring: Measurement of mechanical properties and impact sensitivity

The size of wind turbine blades is increasing in order to improve energy efficiency. However, these large blades cause unexpected problems such as bird collisions. If bird collisions with wind turbine blades can be monitored, birds could quickly be rescued, and the blade structure could be examined to assess whether it has significant damage. In this study, a smart composite blade was fabricated that can operate as an impact sensor as well as perform structural functions. The smart composite blade fabricated in this study was developed by mixing a piezoelectric powder with epoxy resin and impregnating it to glass fiber. It is lighter and more economical than the conventional method. However, when additives are introduced to the resin, structural instability may result. Therefore, the structural characteristics of the smart composite were investigated through tensile tests for specimens with varying amounts of added piezoelectric powder. The experimental results demonstrated that the impact signal was detected even at a very small amount of added piezoelectric powder, and the additives were determined to be helpful in maintaining or increasing structural properties such as the elastic modulus and tensile strength.