- Author
- Cook, G. R. | Simiu, E.
- Title
- Experimental and Numerical Chaos in Continuous Systems: Two Case Studies.
- Coporate
- National Institute of Standards and Technology, Gaithersburg, MD
- Book or Conf
- ACE, EM Div. Mechanics Computing in 1990s and Beyond. May 20-21, 1991, Columbus, OH, 786-790 p., 1991
- Keywords
- offshore platforms | chaotic motion | columns | galloping square bars | numerical simulation | structural systems
- Abstract
- Motivated by recent numerical investigations according to which certain types of deep-water compliant offshore structures may experience undesirable chaotic motions, two types of experimental structural systems capable of exhibiting chaotic or apparently chaotic behavior were studied. The first type of system is a harmonically forced buckled column with a concentrated mass at midspan and with pretensioned continuous springs. For this system a model with acceptable predictive capabilities can be constructed if the continuous springs are represented by a sufficient number of lumped mases with discrete stiffnesses. The second type of system consists either of a galloping square bar or of a pair of parallel, elastically coupled galloping square bars. Our results suggest that the behavior of this type of system, including apparently chaotic behavior, can be described at least to a first approximation by conventional fluidelastic models. However, the predictive capabilities of such models are poor, i.e., in the present state of the art the existence of certain types of hydroelastic behavior may be altogether missed at the design stage. The incorporation of stochastic excitations in the models to account for small flow irregularities may result in improved prediction capabilities.