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Smart Structures and Systems
  Volume 9, Number 4, April 2012 , pages 335-353
DOI: https://doi.org/10.12989/sss.2012.9.4.335
 


A simple method to detect cracks in beam-like structures
Jiawei Xiang, Toshiro Matsumoto, Jiangqi Long, Yanxue Wang and Zhansi Jiang

 
Abstract
    This study suggests a simple two-step method for structural vibration-based health monitoring for beam-like structures which only utilizes mode shape curvature and few natural frequencies of the structures in order to detect and localize cracks. The method is firstly based on the application of wavelet transform to detect crack locations from mode shape curvature. Then particle swarm optimization is applied to evaluate crack depth. As the Rayleigh quotient is introduced to estimate natural frequencies of cracked beams, the relationship of natural frequencies and crack depths can be easily obtained with only a simple formula. The method is demonstrated and validated numerically, using the numerical examples (cantilever beam and simply supported shaft) in the literature, and experimentally for a cantilever beam. Our results show that mode shape curvature and few estimated natural frequencies can be used to detect crack locations and depths precisely even under a certain level of noise. The method can be extended for health monitoring of other more complicated structures.
 
Key Words
    beam-like structures; rayleigh quotient; wavelet transform; natural frequency estimation; crack detection; particle swarm optimization
 
Address
Jiawei Xiang: Department of Mechanical Science and Engineering, Nagoya University, Furo-cho, Chikusa-ku,Nagoya, 464-8603, Japan, College of Mechanical and Electrical Engineering, Wenzhou University, 325035, China
Toshiro Matsumoto : Department of Mechanical Science and Engineering, Nagoya University, Furo-cho, Chikusa-ku,Nagoya, 464-8603, Japan
Jiangqi Long: College of Mechanical and Electrical Engineering, Wenzhou University, 325035, China
Yanxue Wang and Zhansi Jiang : School of Mechanical and Electrical Engineering, Guilin University of Electronic Technology, Guilin, 541004, China
 

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