Experimental results are presented on chaotic oscillations of a post-buckled beam subjected to periodic lateral acceleration. A thin steel beam of thickness 0.198mm, breath 12.7 mm and length 106mm is used as a test beam. Both ends of the beam are clamped and one end is connected to an axial spring. First, natural frequencies of the beam are measured under an axial compression. Under the post-buckled configuration of the beam, characteristics of static deflection by a concentrated load on the beam are obtained. The post-buckled beam shows the soften-and-hardening characteristics of restoring force. The frequency regions of chaotic responses are inspected. The chaotic responses around these domains are examined carefully by time histories, the Poincare´ maps, the Fourier spectra, the maximum Lyapunov exponents and the principal component analysis. The predominant chaotic responses of the beam are generated by the jump phenomena. The chaotic responses are related to the sub-harmonic resonances of 1/2 and 1/3 orders with the lowest mode of vibration. The maximum Lyapunov exponent of the former chaotic response of 1/2 order is larger than that of the latter chaotic response of 1/3 order. Onsets of the chaotic responses are also confirmed by the Poincare´ projection in the variation of exciting frequency.

This content is only available via PDF.
You do not currently have access to this content.