Recursive parameter estimation for the on-line monitoring of delamination growth in composite structures

One of the main failure phenomena in composite materials is delamination, which consists of the progressive separation of plies. An augmented extended Kalman filter (KF) approach for joint input-parameter estimation is proposed and demonstrated in this work for delamination growth monitoring. In particular, a novel recursive estimation scheme for parameter identification is proposed within the joint input-parameter scheme which allows for a substantial reduction of the number of required sensors, enabling the use of the proposed KF approach. The proposed methodology also allows for the full-field response reconstruction, interface stiffness degradation monitoring and critical load identification. The methodology is validated on both simulated as well experimental data of a carbon fiber double Cantilever beam specimen, showcasing good accuracy for both cases.