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Detection of multiple cracks using frequency measurements

DSpace at IIT Bombay

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Title Detection of multiple cracks using frequency measurements
 
Creator PATIL, DP
MAITI, SK
 
Subject modified fourier-series
free-vibration analysis
natural frequencies
elastic-foundation
dynamic behavior
transverse vibration
concentrated masses
bending vibrations
arbitrary number
cantilever beam
transfer matrix method
vibration based detection of multiple cracks
vibration modelling of cracked beam
ndt of cracks
 
Description A method for detection of multiple open cracks in a slender Euler-Bernoulli beams is presented based on frequency measurements. The method is based on the approach given by Hu and Liang [J. Franklin Inst. 330 (5) (1993) 841], transverse vibration modelling through transfer matrix method and representation of a crack by rotational spring. The beam is virtually divided into a number of segments, which can be decided by the analyst, and each of them is considered to be associated with a damage parameter. The procedure gives a linear relationship explicitly between the changes in natural frequencies of the beam and the damage parameters. These parameters are determined from the knowledge of changes in the natural frequencies. After obtaining them, each is treated in turn to exactly pinpoint the crack location in the segment and determine its size. The forward, or natural frequency determination, problems are examined in the passing. The method is approximate, but it can handle segmented beams, any boundary conditions, intermediate spring or rigid supports, etc. It eliminates the need for any symbolic computation which is envisaged by Hu and Liang [J. Franklin Inst. 330 (5) (1993) 841] to obtain mode shapes of the corresponding uncracked. beams. The proposed method gives a clear insight into the whole analysis. Case studies (numerical) are presented to demonstrate the method effectiveness for two simultaneous cracks of size 10% and more of section depth. The differences between the actual and predicted crack locations and sizes are less than 10% and 15% respectively. The numbers of segments into which the beam is virtually divided limits the maximum number of cracks that can be handled. The difference in the forward problem is less than 5%. (C) 2002 . .
 
Publisher PERGAMON-ELSEVIER SCIENCE LTD
 
Date 2011-08-24T00:38:56Z
2011-12-26T12:56:40Z
2011-12-27T05:45:43Z
2011-08-24T00:38:56Z
2011-12-26T12:56:40Z
2011-12-27T05:45:43Z
2003
 
Type Article
 
Identifier ENGINEERING FRACTURE MECHANICS, 70(12), 1553-1572
0013-7944
http://dx.doi.org/10.1016/S0013-7944(02)00121-2
http://dspace.library.iitb.ac.in/xmlui/handle/10054/10704
http://hdl.handle.net/10054/10704
 
Language en