Increasing robustness of solution versus noise for identifying delamination damage in composite plates using a hybrid method

Vibrational methods is one of the common nondestructive damage detection methods for detecting the damage parameters. The most important problem of these methods is their low sensitivity to detect the damage in the presence of noise. In this article, a hybrid damage detection method has been studied to increase the robustness of vibrational method to noise. First, the primary damage location has been detected by the wavelet transform. Next, all the damage parameters including location, depth and intensity of damage have been identified by the model updating process based on the Genetic Algorithm. The signal based on the strain energy ratio in intact and damaged states has been examined to primarily and approximately detect the location of damage thought applying wavelet transform. Also the selected error function in the updating process is based on the strain energy difference between these two states. Using the proposed method leads to raise level of robustness in the presence of noise, also the solution performs faster than the prior methods with the less computational cost. In this work, the solution robustness against noise in traditional model updating method and the proposed hybrid method based on the wavelet transform and updating process has been compared together. The case study has been the laminated composite plate with the delamination damage