Application of Chaos Theory Analysis to Smart Structure Techniques for Highway Infrastructures

摘要

Chaos theory concerns dynamic behavior that is neither purely deterministic nor strictly random.It has several possible applications to smart structures in the highway infrastructures including:long term structural health monitoring,detection of hazardous loading conditions,sensor network optimization,and control of chaotic vibrations.This paper presents recent research at the Turner Fairbank Highway Research Center(TFHRC)of the Federal Highway Administration(FHWA)in application of chaos theory to these topics.This research has included advances in the nonlinear 3-dimensional finite element modeling of highway bridges in order to produce large-scale,high-fidelity computer simulations of bridge dynamics.This has enabled the investigation of loading and structural conditions that give rise to chaotic patterns structural response and also the sensitivity of monitoring systems for detecting damage using chaos parameters.Another area of research concerns the development of improved algorithms used in the analysis of structural response data for chaotic behavior.These include the application of Maximum Entropy to estimate the probability density functions of the response data and the use of non-Gaussian random variables in the approximation of chaotic trajectories by polynomial chaoses.A third research area concerns the writing of user-friendly Windows-based software for chaos theory analysis of highway bridge response data series.The presentation includes the application of these tools to several examples of different types of highway bridge structures including the AASHTO standard steel girder bridge,the Commodore Barry Bridge,the bascule drawbridge span of the new Woodrow Wilson Bridge and the Bill Emerson Cable-Stayed Bridge.This research has confirmed,on the basis of both numerical simulations and analysis of actual monitoring data,that bridges of different structural designs and construction materials can all exhibit chaotic behavior.Therefore chaos theory analysis can be essential in the successful implementation of smart techniques for the highway infrastructure.