Inverse method for identification of edge crack using correlation model

Abstract

Crack in a structural member alters local stiffness that affects the dynamic characteristics such as natural frequency and mode shape of the structure. Identification of crack location and size is one key destination of structural health monitoring. In this paper, we propose a correlation-based inverse method for identification of crack location and size in a cantilever beam. First, natural frequencies of healthy and cracked cantilever beams were computed using finite element method and verified with experimental tests. Next, changes in natural frequencies with respect to crack locations and sizes were analyzed and the correlation model between natural frequency and crack parameters was constructed by non-linear curve-fitting. Finally, in the inverse analysis, correlation model was used to identify crack location and size based on the knowledge of the first and second natural frequencies from the measurements. Results indicate that the inverse method with new correlation model can identify crack location and size. The proposed identification method demonstrated for simple cantilever beam can be adapted for crack identification in complex structures. The proposed method is simple and easy to identify crack location and depth; its main advantage is that knowledge of only the first and second natural frequencies are required to predict crack parameters.

The Vibration Analysis Based on Experimental and Finite Element Modeling for Investigating the Effect of a Multi-Notch Location of a Steel Plate

“…The nature obtained from the FE model was 8.44, 8.70, and 10.10 Hz, respectively; when the trend line was diversified, it could be seen that the obtained higher value A indicates the distance from the notch to the edge of the workpiece H; the smaller the shift, the higher the natural frequency. According to the works of Khoa Viet Nguyen et al [58], C. S. Kumar et al [27], and W. P. P. Aye et al [59], the relationship between the location and size of cracks in beams was first studied. The finite element method calculated the natural frequencies of strong and fractured cantilevers and validated them by experimental testing.…”

Some Studies on Verifying the Applicability of Free Vibration-based Modes Shapes Method to Rectangular Shaped Cracks in a Cantilever Beam

“…Natural frequency was employed as a starting point for identifying crack parameters in this research. Aye and Htike (2019) employed the first two relative natural frequencies to forecast the cantilever beam's crack characteristics. They examined the broken cantilever beams for the first two natural frequencies using experiments.…”