Some Recent Studies on Cracked Rotors

Sekhar, A. S.

doi:10.1007/978-94-007-0020-8_41

Cited by 8 publications

(3 citation statements)

References 67 publications

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“…Many investigators have studied the crack identification problems in structures [1][2][3][4][5][6][7][8][9] . MORASSI [1] proposed a detect method for shaft with an open crack, which is based on the changes in a pair of natural frequencies and closed-form solutions of the structures.…”

Section: Introduction *mentioning

confidence: 99%

“…ANJAN, et al [5] , used an adaptive h-version FEM for structure damage detection in order to control the discretization error because the traditional finite elements are impotent to describe the singular behavior of cracks and numerous elements are needed for numerical computation. GASCH [6] , DIMAROGONAS [7] , SALAWU [8] , and SEKHAR [9] reviewed crack identification methods based on the dynamic behavior changes. And many new methods have also been introduced at the 7th vibration engineering meeting in 2011(VETOMAC 2011).…”

Section: Introduction *mentioning

confidence: 99%

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Three-steps-meshing based multiple crack identification for structures and its experimental studies

Chen

2013

Chin. J. Mech. Eng.

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Multiple crack identification plays an important role in vibration-based crack identification of structures. Traditional crack detection method of single crack is difficult to be used in multiple crack diagnosis. A three-step-meshing method for the multiple cracks identification in structures is presented. Firstly, the changes in natural frequency of a structure with various crack locations and depth are accurately obtained by means of wavelet finite element method, and then the damage coefficient method is used to determine the number and the region of cracks. Secondly, different regions in the cracked structure are divided into meshes with different scales, and then the small unit containing cracks in the damaged area is gradually located by iterative computation. Lastly, by finding the points of intersection of three frequency contour lines in the small unit, the crack location and depth are identified. In order to verify the effectiveness of the presented method, a multiple cracks identification experiment is carried out. The diagnostic tests on a cantilever beam under two working conditions show the accuracy of the proposed method: with a maximum error of crack location identification 2.7% and of depth identification 5.2%. The method is able to detect multiple crack of beam with less subdivision and higher precision, and can be developed as a multiple crack detection approach for complicated structures.

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Section: Introduction *mentioning

confidence: 99%

Section: Introduction *mentioning

confidence: 99%

Three-steps-meshing based multiple crack identification for structures and its experimental studies

Chen

2013

Chin. J. Mech. Eng.

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“…Hong et.al [4] used Lipchitz exponents for the detection of singularities in beam modal data. Wavelet methods integrate structural dynamic parameters like modal frequencies, modal shape, and modal damping with the determined Lipschitz exponent to detect the damage location and depth [5]. Loutridis [6] proposed technique to identify cracks in double-cracked beams using wavelet analysis.…”

Section: Introductionmentioning

confidence: 99%

Damage Identification and Quantification in Structures Using Wavelet Analysis

Chandra

Sekhar

2013

AMM

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In this study, displacement and strain energy mode shapes obtained from the structure, are processed using continuous spatial wavelet transforms for damage identification. A cantilever and simply supported beam are analysed in ANSYS to obtain mode shapes by performing modal analysis both for damaged and undamaged conditions. Different wavelets are processed to choose the best mother wavelet for detecting crack, a representation of damage. The dimensions of crack like depth are varied from 0.5 mm. Spatial distribution of wavelet coefficients obtained is used for identifying the damage. The quantification of the damage is done by using Lipchitz constant. It is observed that by using strain energy mode shapes the percentage of damage (crack) identification level can be improved than by using displacement mode shapes. The minimum damage level that the strain mode shape can identify is approximately 3% of the element thickness, whereas with displacement mode shapes, it is about 7% of the element thickness. Different types of crack configurations like single surface crack, double surface cracks and internal cracks are simulated and studied using both the modal methods. It is observed that the strain energy mode method could identify internal cracks also.

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