Structural Damage Identification Based On Chaos Incentive

Structual health monitoring is a hot research topic in the field of civil engineering at present, while damage identification technique is one of key issues. For damage identification, this thesis proposes a qualitative identification method based on chaotic attractor and a quantitative identification method based on the kalman filtering algorithm.Chaos discipline is the core content of nonlinear science. And attractor is the main part in the chaos.In recent years, the engineering application algorithms based on chaotic attractor become a focus research topic. This thesis proposes a method based on the embedded technology to reconstruct the equivalent phase space. And recognize the damage according to the distance between the phase point. Cases of univariate and multivariate are discussed respectively. The phase space embedding approach is one of the key technologies of chaotic attractor study. How to decide reconstruction parameters for the phase space embedding approach is also studied. Influence of noise on identification results are also analyzed at the same time. Finally, this algorithm is verified by numerical simulation and experimental analysis.Kalman filtering algorithm is a good estimation method in the linear system, which is widely used in many fields. This paper proposes a new improved method based on the traditional kalman filtering algorithm, that is according to the structural response and external incentive, it can-directly identify the structural parameters such as-stifness, damping and mass of the structure. Through identifying the change of the stiffness, this method can get the quantitative assessment of structure damage. This paper also discusses the influence of the initial value and noise on the recognition result. At the same time for the influence of noise, using samples of extreme value point is proposed in this thesis to deal with the signal containing noise. In this thesis, in addition to the numerical simulation, experiments on a five-floor steel frame structure is conducted to verify the methods.Analysis results of numerical simulation and experimental show the effectiveness of the proposed qualitative identification method based on chaotic attractor and quantitative identification method based on improved kalman filtering algorithm.