Delamination detection in composite laminates using low frequency guided waves: Numerical simulations

The aim of this study is to find an efficient way of finite element modelling of guided wave propagation in composite laminates to detect delaminations. A novel approach is proposed to model delaminations by locally reducing the stiffness and it is implemented in a finite element shell model. The approach is verified by comparing the results with the results of two existing approaches. Results show that the stiffness reduction approach gives reasonable accuracy for the primary wave modes and improvement in simulation time. Moreover, it is shown that new convergence criteria should be considered to simulate the guided wave propagation. Additionally, the Pearson correlation coefficient is introduced as a good criterion for delamination detection in such problems. All the conclusions are made when simulations are performed in the low frequency range and can be used to study guided wave propagation in large composite structures such as wind turbine blades.