Vibrational power flow analysis of cracked functionally graded beams

• Published in: Thin-walled structures 2020-05, Vol.150, p.106626, Article 106626
• Main Authors: Zhu, Lin-Feng, Ke, Liao-Liang, Xiang, Yang, Zhu, Xin-Qun, Wang, Yue-Sheng
• Format: Article
• Language: English
• Subjects: Continuous wavelet transform; Damage identification; Edge crack; Functionally graded beam; Vibrational power flow
• ISSN: 0263-8231; 1879-3223
• DOI: 10.1016/j.tws.2020.106626

In this paper, the vibrational power flow of a cracked beam made of functionally graded materials (FGMs) is investigated. The Young's modulus and mass density change exponentially along the thickness direction of the beam. The cracked FGM beam is divided into two sub-beams at the crack section which are connected by a massless rotational spring. Based on the Timoshenko beam theory, the governing equations of the cracked FGM beam are derived by using the neutral plane as the reference plane. The dynamic response of the FGM beam subjected to a harmonic concentrated transverse force is solved by the wave propagation approach. The input power flow and the transmitted power flow are obtained. The effect of the crack location and depth and the Young's modulus ratio on the input power flow and the transmitted power flow is studied in detail. A new damage index (DI) for the crack identification of FGM beams is proposed by applying continuous wavelet transform (CWT) to the transmitted power flow distribution along the beam longitudinal direction. The peak of DI indicates the crack location in FGM beams with small crack depth. [Display omitted]