One of the classical features exhibited in nonlinear dynamics of engineering systems is the jump phenomenon, which is the discontinuous change in the steady state response of a system as a parameter is slowly varied. Such phenomenon is characterized by large amplitude dynamic responses of systems to small amplitude disturbances. It is established that this phenomenon cannot be described by the standard asymptotic and perturbation methods because they are limited to the study of small amplitude responses to small disturbances. Therefore, this paper presents the application of differential transformation method-Padé approximant to the solution of jump and bifurcation phenomena for a geometrical nonlinear cantilever beam subjected to a harmonic excitation. The accuracy and validity of the analytical solutions obtained by the differential transformation method are shown through a comparison of the results of the analytical solution with the corresponding results of the numerical solution obtained by fourth-order Runge-Kutta method and also with the results in a past study using harmonic balancing method. With the aid of the differential transformation method-Padé approximant, the effects of the nonlinear parameters in the model equation on the dynamic response of the beam are investigated. Also, the sensitivity of the beam to the external excitation amplitude is analyzed. In the distributed forced vibration, the jump phenomenon appeared in the response amplitude by variation of the excitation frequency while in the resonance frequency, the beat phenomenon with harmonic motion is seen for low level of excitation amplitude. At a certain frequency, the jump and bifurcation phenomena are seen in the curves of responses versus excitation amplitude. Additionally, the plots of the phase plane and time history of the system response are shown. It is established that the differential transformation method is a very useful mathematical tool for dealing with the nonlinear problems.
Financed by the National Centre for Research and Development under grant No. SP/I/1/77065/10 by the strategic scientific research and experimental development program:
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