Assessment of delamination location in composite laminates based on a chaotic oscillator method



The work aims to study the assessment of delamination location in composite laminates using vibration measurement with a chaotic oscillator method. Delamination is a type of damage that commonly occurs in composite laminates, which can cause a severe degradation of their material properties. The traditional vibration-based methods can encounter difficulties in detecting and locating these delamination-type damages especially when the size of delamination is relatively small and there is a significant level of noise in its vibration measurement. With this particular consideration, a vibration-based method using a non-linear chaotic oscillator was used in this study due to its sensitivity to the change in vibration signal characteristics. A numerical model of composite laminates with delamination damage under harmonic excitation was developed and the vibration signal obtained from composite laminates was processed using the chaotic oscillator method. A feature named Lyapunov Exponent (LE) was used as a delamination damage index to describe the characteristics of the chaotic oscillator for cases with delamination at varying structural locations. The effects of delamination locations on the developed damage index were analyzed in this work. The results showed that there was a strong correlation between the delamination location and the LE feature, even for the case with a relatively high level of measurement noise. The results demonstrated the effectiveness of the method to identify delamination in composite laminates, which has also the potential to be used to detect other types of damages.