Abstract
Experimental results are presented on chaotic vibrations of a post-buckled cantilevered beam connected to a spring-mass system by a string. The string is stretched between the beam end and leaf springs of spring-mass system on a base. Applying tensile force to the string, the beam is compressed, and then the beam is buckled to a post-buckled state. The axial force and the shearing force of the beam are varied due to the geometrical configuration of deflection of the beam and the displacement of the leaf spring. The beam is subjected to lateral periodic acceleration, chaotic responses are observed in typical frequency region. Predominant chaotic responses are examined by the Fourier spectrum, the Poincare map and the maximum Lyapnov exponents. Contributions of vibration modes to the chaotic responses are analyzed by the principal component analysis. Increasing the amount of the mass in the spring-mass system, the maximum Lyapnov exponents and the corresponding embedding dimension increase. The figure of the Poincare map looses the focus due to the increase of the maximum Lyapnov exponents.
