Three-dimensional deflection estimation of a composite blade using a modal approach based shape estimation algorithm with embedded sensor array

Abstract

Real-time deflection monitoring of a composite wind blade was conducted using a shape estimation algorithm using modal approach with strain data. The strain data was measured by fiber Bragg grating (FBG) sensors embedded in pressure side skin of the blade. The displacement-strain transformation (DST) matrix on the basis of the modal approach was obtained by the finite element model of the composite structure. The locations of the nine FBG strain sensors were optimized by minimizing the condition number of the displacement-strain transformation matrix. The deflection-monitoring test of the 11m span composite blade was conducted to verify the shape reconstruction algorithm and applicability of the FBG sensors in deflection shape estimation. The estimated shapes measured by FBG sensors are compared with the directly captured deflection shapes measured by stereo pattern recognition (SPR) cameras.