EXPERIMENT ON CHAOTIC OSCILLATIONS OF A POST-BUCKLED REINFORCED BEAM CONSTRAINED BY AN AXIAL SPRING

Experimental results are presented on chaotic oscillations of a post-b uckled reinforced beam subjected to lateral excitations. The beam is p artially reinforced and is clamped at both ends. One end of the beam i s arranged to move to an axial displacement by an elastic spring. The beam is deformed to a post-buckled configuration by the axial constrai nt. Under the post-buckled condition of the beam, chaotic responses ar e generated in specified regions of exciting frequency. The chaotic re sponses are examined by the Fourier spectrum, the Poincare projection and the maximum Lyapunov exponent. It is found among other things that the chaos of the reinforced beam is mainly generated with the lower m odes of vibration. The instability regions of chaos as well as the eff ect of inertia in the axial direction are also examined.