Generalised local entropy analysis for crack detection in beam-like structures

Abstract

Generally, cracks would lead in local discontinuity and sudden change in mode shape, and the local entropy of beam mode will change with the discontinuity of mode shape. Based on this property, cracks can be detected without using a healthy mode shape serving as the baseline. This paper presents a generalised local entropy (GLE) analysis method for crack detection in beam structures, which is a non-baseline mode shape-based damage detection algorithm for beam-type structures. The fundamental and the second-order vibration modes of a cracked cantilever beam are analysed with the presented method. The proposed prediction scheme is validated by simulations and experiments. Based on the results obtained in this paper and the qualities of simplicity and efficiency of GLE method, a mode shape-based crack identification approach is developed as an alternative damage index for structural health monitoring and non-destructive testing.

Keywords::

• local entropy
• crack detection
• beam
• mode shape
• non-destructive testing

Acknowledgements

This work was supported by the National Natural Science Foundation of China [grant number 51225501, 51175401 and 51035007], the Research Fund for the Doctoral Program of Higher Education of China [grant number 20120201110028] and the Program for Changjiang Scholars and Innovative Research Team in University.

Notes

^1. Email: [email protected]