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Response Simulation of Non-Classically Damped Structures using Modal and Stochastic Subspace Identification

Saeedanezhad, Ali | 2016

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  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 48731 (09)
  4. University: Sharif University of Technology
  5. Department: Civil Engineering
  6. Advisor(s): Ahmadizadeh, Mehdi
  7. Abstract:
  8. As more structures are equipped with supplemental energy dissipation devices, the assumption of classical damping becomes less accurate. For this reason, development of a general identification method that is accurate enough for response simulation is emparative for such structures. Modal identification of structures can be carried out using either modal or state space approach. In modal methods (such as wavelet transform method), the damping matrix needs to be identified for response simulation. This is sometimes difficult, and may result in simulation inaccuracies. In contrast, direct identification of damping matrix for simulation is not required in state space approach. Hence, the Stochastic Subspace Identification method has been used in this study to develop a suitable method for identification of structures with arbitrary damping models.For this purpose a method has been developed for direct identification of damping matrix using an incomplete set of dynamic modes of vibration. This allows for the elimination of higher modes, which may be significantly contaminated with noise and other errors. The numerical and experimental evaluations of these methods demonstrate that they are able to provide acceptable accuracy for response simulation of nonclassical structures. Furhtermore, the identified damping matrices from the proposed damping identification technique show that the real damping mechanism may be significantly different from the usual linear viscous damping. While the identified damping matrices are shown to differ from the presumed values, it is shown that the damping ratios are determined accurately, leading to proper simulation of structural response
  9. Keywords:
  10. System Identification ; Structural Health Monitoring ; Stochastic Subspace Identification ; Wavelet Transform ; Damped Structures ; Experimental Modal ; Frequency Domain Decomposition ; Non-Classical Damping ; Response Reproduction

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