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STUDY OF THE BREATHING MECHANISM OF AN ELLIPTICAL CRACK IN A ROTATING SHAFT WITH AN ECCENTRIC MASS

Muñoz-Abella, B.; Rubio, P.; Montero, L.; Rubio, L.;

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Rotative machinery (blades, rotors, compressors,..) are used quite often in several industries such as aerospace, nuclear, oil, transportation and industry processes in general. Operation failures of this kind of machinery are related with the presence and growing of fatigue cracks in one of the main components: the shafts. The shafts, that perform in bend- ing and torsion, present additionally misalignments or/and unbalances that alter the normal function of the components. The unbalance in a rotating system can be produce by a eccen- tric mass. When a cracked shaft rotates, the crack opens and closes in what is called the breathing mechanism in which the crack passes from an open state to a close state with a transition between both situations producing a partial opening or closing of the crack. On the other hand it is very frequent to consider cracks with straight fronts, but the experience shows that most of the cracks that appear in rotating shafts are elliptical. In this paper we present the numerical model (Finite Element Method) of the quasi-static behaviour of an unbalance cracked shaft (with elliptical front) considering an eccentric mass. The model chosen for this study is the classical Jeffcott rotor. To simulate the rotation of the shaft, different angular positions have been considered. The influence of the mass eccentricity in the opening of the crack has been studied considering different angles of eccentricity measured from the position of the crack. In this paper we present the comparison of the partially opening/closing of the crack considering different angles of rotation and different positions of the eccentricity. The work allows to know the influence of the unbalance of rotating shafts in the crack breathing mechanism and will allow to predict the influence of this behavior on the values of the Stress Intensity Factor and in the propagation of cracks.

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Palavras-chave: shaft, elliptical crack, eccentricity, breathing mechanism, rotative machinery.,

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DOI: 10.5151/meceng-wccm2012-18251

Referências bibliográficas
  • [1] Bachschmid N., Pennacchi P., Tanzi E., “Some remarks on breathing mechanism, on non- linear effects an on slant and helicoidal cracks”. MSSP 22, 879-904, 2008.
  • [2] Carpinteri A., Brighenti R., Spagnoli A., ”Surface flaws in cylindrical shafts under rotary bending”. Fatigue Fract. Eng. Mat. Struct. 21, 1027-1035,1998.
  • [3] Cheng L., Li N., Chen X.F., He Z.J., “The influence of crack breathing and imbalance orientation angle on the characteristics of the critical speed of a cracked rotor”. J.Sound Vib. 330, 2031-2048, 2011.
  • [4] Couroneau N., Royer J., ”Simplified model for the fatigue growth analysis of surface cracks in round bars under mode I”. Int. J. Fatigue 20, 711-718, 1998.
  • [5] Darpe A.K., Gupta K., Chawla A., “Transient response and breathing behaviour of a cracked Jeffcott rotor”. J.Sound Vib. 272, 207-243, 2004.
  • [6] Darpe A.K., Gupta K., Chawla A., “Dynamics of a bowed rotor with a transverse surface crack”. J.Sound Vib. 296, 888-907, 200
  • [7] Darpe A.K. “A novel way to detect transverse surface crack in a rotating shaft”. J.Sound Vib. 305, 151-171, 200
  • [8] Dimarogonas A.D., Papadopoulos C.A., “Vibration of cracked shafts in bending”. J.Sound Vib. 91, 583-593, 1983.
  • [9] Jun O.S., Gadala M.S., “Dynamic behaviour analysis of a cracked rotor”. J.Sound Vib. 309, 210-245, 2008.
  • [10] Patel T.H., Darpe A.K. “Influence of crack breathing model on nonlinear dynamics of a cracked rotor”. J.Sound Vib. 311, 1953-1972, 2008.
  • [11] Penny J.E.T., Friswell M.I., “Simplified modelling of rotor cracks”. Proc. of ISMA: Int. Conf. on Noise and Vibration engineering 2, 607-615, 2002.
  • [12] Rubio L., Muñoz-Abella B., Rubio P., Montero L., “Influence of the eccentricity in the crack breathing in a rotating shaft”. Proc. 8th Int. Conf. Eng. Comp. Tech.ECT. Croatia, 20
  • [13] Rubio L., Muñoz-Abella B., Loaiza G., “Static behaviour of a shaft with an elliptical crack”. Mech. Syst. Signal Pr. 25, 1674-1686, 2011.
  • [14] Sekhar A.S., Prabhu B.S. ”Condition monitoring of cracked rotors through transient re- sponse”. Mech. Mach. Theory 33, 1167-12751, 1998.
  • [15] Shin C.S., Cai C.Q., ”Experimental and finite element analyses on stress intensity fac- tors of an elliptical surface crack in a circular shaft under tension and bending”. Int. J. Fracture 129, 239-264, 2004.
Como citar:

Muñoz-Abella, B.; Rubio, P.; Montero, L.; Rubio, L.; "STUDY OF THE BREATHING MECHANISM OF AN ELLIPTICAL CRACK IN A ROTATING SHAFT WITH AN ECCENTRIC MASS", p. 1045-1055 . In: In Proceedings of the 10th World Congress on Computational Mechanics [= Blucher Mechanical Engineering Proceedings, v. 1, n. 1]. São Paulo: Blucher, 2014.
ISSN 2358-0828, DOI 10.5151/meceng-wccm2012-18251

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