System identification of a beam with frictional contact

Document Type : Research Article

Author

Assistant professor, School of Mechanical Engineering, Arak University of Technology, Arak, Iran

Abstract

The nonlinear system becomes an area with numerous investigations over the past decades. The conventional modal analysis could not be  applied on nonlinear continuous system which makes it impossible to construct the reduced order models and obtain system response based on limited number of measurement points. Nonlinear normal modes provide a useful tool for extending modal analysis to nonlinear systems but the extraction of nonlinear normal modes is cumbersome. In this research by neglecting the damping effect on response shape, the nonlinear joint in frictional beam is replaced by 3 order nonlinear spring. The equation of motion is solved using the method of multiple scales up to third super harmony which are neglected in most system identification practices. It is shown in an experimental test set-up, the general form of solution can regenerate observed response of any point and more important similar to linear system, the single mode would be sufficient in analysis when excitation frequency is close to resonant frequency.

Highlights

  • Dynamic characteristics of a frictional contact are investigated
  • The equation of motion is solved using the method of multiple scales
  • Higher harmonies are included in identification process
  • Unknown response of any point could be regenerated by solution

Keywords


[1] A.A. Ferri, Friction damping and isolation systems, Journal of mechanical Design, 117 (1995) 196-206.
[2] E.J. Berger, Friction modeling for dynamic system simulation, Applied Mechanics Reviews, 55 (2002) 535-577.
[3] R.A. Ibrahim, C.L. Pettit, Uncertainties and dynamic problems of bolted joints and other fasteners, Journal of sound and Vibration, 279 (2005) 857-936.
[4] A.F. Vakakis, Analysis and identification of linear and nonlinear normal modes in vibrating systems, (1991).
[5] G. Kerschen, M. Peeters, J.-C. Golinval, A.F. Vakakis, Nonlinear normal modes, Part I: A useful framework for the structural dynamicist, Mechanical Systems and Signal Processing, 23 (2009) 170-194.
[6] M. Peeters, R. Viguié, G. Sérandour, G. Kerschen, J.-C. Golinval, Nonlinear normal modes, Part II: Toward a practical computation using numerical continuation techniques, Mechanical systems and signal processing, 23 (2009) 195-216.
[7] H. Ahmadian, H. Jalali, F. Pourahmadian, Nonlinear model identification of a frictional contact support, Mechanical Systems and Signal Processing, 24 (2010) 2844-2854.
[8] H. Jalali, H. Ahmadian, F. Pourahmadian, Identification of micro-vibro-impacts at boundary condition of a nonlinear beam, Mechanical Systems and Signal Processing, 25 (2011) 1073-1085.
[9] J.A. Turner, Non-linear vibrations of a beam with cantilever-Hertzian contact boundary conditions, Journal of sound and Vibration, 275 (2004) 177-191.
[10] A.H. Nayfeh, D.T. Mook, Nonlinear Oscillations, Wiley, New York, 1979, LD Landau and E. M. Lifshitz, Mechanics (Pergamon, New Y'ork, 1976),  338-348.