The mass, stiffness, and geometrical dimensions of the variable cross-section beams vary along their length. This renders the rapid and accurate obtainment of crack information using conventional methods challenging. Thus, a digital twin (DT) model driven by a mechanism twin model and real-time monitoring data is proposed for fast and precise identification of single crack in this study. Based on the stiffness and mass, the mechanism twin model calculates the equivalent geometric dimensions of the beam, and they are combined with the first natural frequency to drive a data twin model to facilitate rapid and accurate calculation of the second and third natural frequencies of the sound beam. The monitoring data are decomposed by the DT model to obtain the modal shapes and curvatures for crack position identification, and the variations in the natural frequencies are obtained by comparing the decomposed and calculated results. The variations and crack position are the dependent variables of the crack length/depth, and the crack dimension is rapidly identified using the data twin model. Furthermore, numerical simulations and actual experiments are performed to demonstrate the effectiveness of the method. Thus, this study proposes a DT model to quickly and accurately identify cracks in variable section beams, thereby providing a reliable and efficient tool for the prognostic and health management of equipment.
Yang et al. (Wed,) studied this question.