Loading...
Search for:
stochastic-subspace-identification
0.006 seconds
Output-Only Modal Identification of an Offshore Jacket Platform
, M.Sc. Thesis Sharif University of Technology ; Golafshani, Ali Akbar (Supervisor)
Abstract
Extracting modal parameters is necessary for future vibration-based health monitoring studies of the structures. Due to the reason that it is difficult to measure the input excitation forces acting on a real large structure in its operational condition, it is preferable to use the output-only methods which estimate the modal model by using responses data only. Also, the output-only dynamic testing has advantages of being inexpensive since no equipment is needed to excite the structure and the service condition does not have to be interrupted.This paper presents the results of modal identification of an offshore jacket platform using output-only methods with the assumption of ambient...
Experimental and analytical model analysis of Babolsar's steel arch bridge
, Article 3rd International Conference on Bridge Maintenance, Safety and Management - Bridge Maintenance, Safety, Management, Life-Cycle Performance and Cost, Porto, 16 July 2006 through 19 July 2006 ; 2006 , Pages 235-237 ; 0415403154 (ISBN); 9780415403153 (ISBN) ; Kazemi, M. T ; Lark, B ; Tabrizian, Z ; Sharif University of Technology
Taylor and Francis/ Balkema
2006
Abstract
The paper presents the experimental and analytical model analysis of a steel-girder arch bridge. The field test is carried out by ambient vibration testing under traffic excitations. Both the peak picking method in the frequency domain and the stochastic subspace identification method in the time domain are used for the output-only model identification. A good agreement in identified frequencies has been found between the two methods. It is further demonstrated that the stochastic subspace method provides better mode shapes. The three-dimensional finite element models are constructed and an analytical model analysis is then performed to generate natural frequencies and mode shapes in the...
Response Simulation of Non-Classically Damped Structures using Modal and Stochastic Subspace Identification
, M.Sc. Thesis Sharif University of Technology ; Ahmadizadeh, Mehdi (Supervisor)
Abstract
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...
Automatic System Identification Algorithm Including Uncertainty Estimation based on Operational Modal Analysis
, M.Sc. Thesis Sharif University of Technology ; Khodaygan, Saeed (Supervisor) ; Movahedi, Mohammad Reza (Supervisor)
Abstract
Modal analysis is very important in determining the physical properties of structures and mechanisms. This field is divided into two general parts: Experimental Modal Analysis (EMA) and Operational Modal Analysis (OMA). In the operational modal analysis, there are more challenges for the analyst due to the lack of inputs to identify the system. Many of the mechanical structures can not be analyzed experimentally and under specific loadings, but should be identified under actual operating conditions and in situations where the inputs of the system are not measurable. For this purpose, a modal analysis method called "Random Sub-Space Identification" (SSI) is intoduced, which uses only output...