WJM  Vol.1 No.2 , April 2011
Nonlinear Dynamic Characteristics of a Simple Blade with Breathing Crack Using Ansys Software
ABSTRACT
Nonlinear dynamic response represents the most important studies for structures subjected to a dynamic mo-tion so that it provides the researcher by an excellent information especially at critical design levels. The un-predictable nonlinearity in the structure appears when damage is inherited. Most times, the failure of the structure is related to the dynamic nonlinearity. With regard to the breathing phenomena for nonlinear struc-tural systems, very little is known about how the nonlinearities influence the response and the dynamic char-acteristics of cracked structures. In this research, dynamic nonlinearity is presented in damaged structure due to presence of a crack. The crack is assumed to be open and close simultaneously and then breathing. Effect of breathing phenomenon was studied deeply. Crack breathing is simulated at the crack surfaces using con-tact elements. The contact, geometrical, penalty, and spin stiffnesses are taken in consideration. In addition, effect of several important parameters such as rotor angular velocity and crack ratio are studied. The study showed that the breathing natural frequency of any structure is ranged between opened (no contact) and closed crack natural frequencies. The larger crack length, the more nonlinear disturbance in the dynamic re-sponse behavior. Also, at a critical crack length, some mode shapes tend to exchange and pass over with other modes. The presence of the mode interchanging and mode crossover was a guide on the nonlinear re-sponse for the cracked structure. The numerical modeling is achieved using ANSYS finite element program. Experimental data are used for validating the accurate use of contact elements in ANSYS environment.

Cite this paper
nullS. Waheed, N. Mostafa and D. Jawad, "Nonlinear Dynamic Characteristics of a Simple Blade with Breathing Crack Using Ansys Software," World Journal of Mechanics, Vol. 1 No. 2, 2011, pp. 21-30. doi: 10.4236/wjm.2011.12004.
References
[1]   V. Khoa and O. Olatunbosun, “A Method for Remote Monitoring of Structural Health Based on the Nonlinear Phenomenon in Dynamic Response of Damaged Structures,” Proceedings of the World Congress on Engineering, London, 2-4 July2007.

[2]   S. Benfratellol, P. Cacciola, N. Impollonia, A. Masnata and G. Muscolino, “Crack Identification in a Beam by Measure of the Response to White Noise,” Computers & Structures, Vol. 81, No. 18-19, 2006, pp. 1773-1782.

[3]   A. Saito, M. P. Castanier and C. Pierre, “Estimation and Veering Analysis of Nonlinear Resonant Frequencies of Cracked Plates,” Journal of Sound and Vibration, Vol. 326, No. 3-5, 2009, pp. 725-739.

[4]   A. Bazoune, “Survey on Modal Frequencies of Centrifugally Stiffened Beams,” The Shock and Vibration Digest, Vol. 37, No. 6, 2005, pp. 449-469. doi:10.1177/0583102405056752

[5]   Y. Chou and W. Yeh, “Prediction of Rotating Blade Modes from Measured Non-Rotating Modal Parameters,” Journal of Vibration and Acoustics, Vol. 113, No. 4, October 1991, pp. 423-557.

[6]   S. Christides and A. Barr, “One-Dimensional Theory of Cracked Bernoulli–EULER Beams,” International Journal of Mechanical Sciences, Vol. 26, No. 11-12, 1984, pp. 639-648. doi:10.1016/0020-7403(84)90017-1

[7]   M. Shen and C. Pierre, “Natural Modes of Bernoulli– Euler Beams with Symmetric Cracks,” Journal of Sound and Vibration, Vol. 138, No. 1, 1990, pp. 115-134. doi:10.1016/0022-460X(90)90707-7

[8]   M. Shen and C. Pierre, “Free Vibrations of Beams with a Single-Edge Crack,” Journal of Sound and Vibration, Vol. 170, No. 2, 1994, pp. 237-259. doi:10.1006/jsvi.1994.1058

[9]   T. G. Chondros, A. D. Dimarogonas and J. Yao, “A Continuous Cracked Beam Vibration Theory,” Journal of Sound and Vibration, Vol. 215, No. 1, 1998, pp. 17-34. doi:10.1006/jsvi.1998.1640

[10]   P. Gudmundson, “The Dynamic Behavior of Slender Structures with Cross-Sectional Cracks,” Journal of the Mechanics and Physics of Solids, Vol. 31, No. 4, 1983, pp. 329-345. doi:10.1016/0022-5096(83)90003-0

[11]   S. M. Cheng, A. S. Swamidas, X. J. Wu and W. Wallace, “Vibrational Response of a Beam with a Breathing Crack,” Journal of Sound and Vibration, Vol. 225, No. 1, 1999, pp. 201-208. doi:10.1006/jsvi.1999.2275

[12]   W. L. Bayissa and N. Haritos, “Experimental Investigation into Vibration Characteristics of a Cracked RCT- Beam,” Melbourne University Private Ltd Report, 2006.

[13]   S. S. Ki and J. H. Kim, “Rotating Composite Beam with a Breathing Crack,” Composite Structure, Vol. 60, No. 1, 2003, pp. 83-90.

[14]   T. G. Chondros, A. D. Dimarogonas and J. Yao, “Vibration of a Beam with a Breathing Crack,” Journal of Sound and vibration, Vol. 239, No. 1, 2001, pp. 57-67. doi:10.1006/jsvi.2000.3156

[15]   X. S. Andreas and A. Polycarpou, “Measurement and Modeling of Normal Contact Stiffness and Contact Damping at the Meso Scale,” ASME Transactions of the ASME, Vol. 127, February 2005.

[16]   C. C. Ma and C. H. Huang, “Experimental and Numerical Analysis of Vibrating Cracked Plates at Resonant Frequencies,” Experimental Mechanics, Vol. 41, No. 1, 2001, pp. 8-18. doi:10.1007/BF02323099

[17]   M. Kulyk, O. Kucher, V. Kharyton, J. Laine and F. Thouverez, “Dynamic Nonlinear Analysis of Cracked Blade,” Journal of Aviation, Vol. 12, No. 3, 2008, pp. 66-79. doi:10.3846/1648-7788.2008.12.66-79

[18]   S. S. Rao, “The Finite Element Method in Engineering,” Fourth Edition, Elsevier Science & Technology Books, 2004.

[19]   A. Saito, M. P. Castanier, C. Pierre and O. Poudou, “Efficient Nonlinear Vibration Analysis of the Forced Response of Rotating Cracked Blades,” Journal of Computational and Nonlinear Dynamics, Vol. 4, No. 1, January 2009, pp. 011005.

[20]   ANSYS, “Engineering Analysis System Theoretical Manual,” http://www. Ansys. Com. Ansys, Version 11, 2007.

[21]   P. Cacciola, N. Impollonia and G. Muscolino, “Crack Detection and Location in a Damaged Beam Vibrating under White Noise,” Computers & Structures, Vol. 81, No. 18-19, 2003, pp. 1773-1782. doi:10.1016/S0045-7949(03)00201-3

 
 
Top