Periodic and Chaotic Motions of a Modified Stoker Column: Experimental and Numerical Results

摘要

Records are presented of typical measured motion of a modified forced Stoker column, including periodic motion around a stable fixed point, periodic snap-through motion, and chaotic motion. Characterizations of the recorded chaotic motion include: the auto-correlation function; the spectral density plot; capacity dimensions; and the Lyapounov exponent. Two sets of numerical simulations were performed, in which the same spring stiffnesses (measured under static conditions) and the same dissipative forces (based on the viscous damping model) were used. The first set, in which the device was modeled as a multidegree of freedom system to account for the distributed mass and stiffness of the springs, yielded chaotic motions qualitatively similar to those recorded in the laboratory. No chaotic motions could be obtained from the second set, which did not reflect the fact that the spring properties are distributed and in which the device was therefore modeled as a one degree of freedom system.