- Author
-
Cook, G. R.
|
Simiu, E.
- Title
- Periodic and Chaotic Motions of a Modified Stoker Column: Experimental and Numerical Results.
- Coporate
- National Institute of Standards and Technology, Gaithersburg, MD
- Report
-
NIST BSS 168
February 1990
44 p.
- Distribution
- Available from Government Printing Office
- Keywords
-
buckling
|
chaotic motion
|
dynamical systems
|
nonlinearity
|
structural dynamics
|
structural engineering
|
vibrations
|
structural systems
- Abstract
- Records are presented of typical measured motions 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 autocorrelation 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. To the writers' knowledge this is the first reported instance of an experimental structural system with continuous members for which a qualitatively successful simulation of the chaotic motion appears to necessitate the inclusion in the model of additional degrees of freedom to account for the effects of continuity.