Accession Number : AD0682957

Title :   DYNAMIC STABILITY OF A PENDULUM UNDER PARAMETRIC EXCITATION.

Descriptive Note : Scientific interim rept.,

Corporate Author : MASSACHUSETTS INST OF TECH CAMBRIDGE AEROELASTIC AND STRUCTURES RESEARCH LAB

Personal Author(s) : Dugundji,John ; Chhatpar,Chandramohan K.

Report Date : DEC 1968

Pagination or Media Count : 112

Abstract : As background for the dynamic stability of structures, a pendulum undergoing parametric excitation is examined in detail. Theoretically, transient and steady state solutions were developed here for both linear and nonlinear theory. The linear theory showed the presence of various instability regions, and of 'beats' and 'waviness' in the response. The nonlinear theory showed the presence of various steady state limit cycles including some little known subharmonic resonances at 1/3, 1/4, 1/5 of the forcing frequency. The effects of initial amplitudes and phasing were determined by state plane diagrams and by analog computer simulation. Experimentally, the pendulum was excited and both transient and steady state records were obtained. Good agreement was obtained with the linear theory at small amplitudes and with the nonlinear theory at large amplitudes. (Author)

Descriptors :   (*STRUCTURES, *VIBRATION), STABILITY, EXCITATION, NONLINEAR SYSTEMS, DIFFERENTIAL EQUATIONS, DAMPING, HARMONIC ANALYSIS, HARMONIC GENERATORS, TRANSIENTS, RESONANCE, RESPONSE, SIMULATION

Subject Categories : Structural Engineering and Building Technology
      Mechanics

Distribution Statement : APPROVED FOR PUBLIC RELEASE