scholarly journals INTEGRATING MODAL ANALYSIS AND SEISMIC INTERFEROMETRY FOR STRUCTURAL DYNAMIC RESPONSE: THE CASE STUDY GIOTTO’S BELL TOWER IN FLORENCE (ITALY)

2019 ◽  
Author(s):  
Giorgio Lacanna ◽  
Renato Lancellotta ◽  
Maurizio Ripepe
Keyword(s):  
Dynamic Response ◽  
Modal Analysis ◽  
Seismic Interferometry ◽  
Structural Dynamic ◽  
Bell Tower

Dynamics-Based Health Monitoring of Wind Turbine Rotor Blades Using Integrated Inertial Sensors

2012 ◽  
Author(s):  
Scott R. Dana ◽  
Douglas E. Adams
Keyword(s):  
Dynamic Response ◽  
Wind Turbine ◽  
Modal Analysis ◽  
Turbine Rotor ◽  
Vertical Shear ◽  
Aerodynamic Load ◽  
Test Bed ◽  
Horizontal Axis Wind Turbine ◽  
Structural Dynamic ◽  
Wind Turbine Rotor

By analyzing the rotor structural dynamic response of a wind turbine, this research aims to improve decision making in operation and maintenance. To illustrate the potential of this measurement technique, a horizontal axis wind turbine test-bed is used to experimentally simulate the rotor structural dynamic response to uniform flow as well as horizontal and vertical shear flow across the rotor plane. The structural dynamic characteristics of the wind turbine rotor are described in the context of modal analysis where each mode of vibration occurs at a particular frequency with a particular modal deflection shape. These deflection shapes facilitate the effectiveness with which a given aerodynamic load couples into the rotor to produce mechanical power in addition to vibrations of the rotor. Operational modal analysis is used to explore the effects of changes in the wind state on the sensitivity of condition monitoring data to two types of damages in the turbine rotor, ice accretion and blade root cracking. Additionally, the degree to which various damage mechanisms can be identified in the presence of yaw and pitch set points is analyzed. It is shown that certain frequencies in the measured response using the flap, edgewise, and span directions of the wind turbine are sensitive to a change in condition of the rotor for use in detecting that type of damage. By analyzing the changes in the modal response amplitudes, the type of damage present in the rotor system can also be classified.

Synergistic application of operational modal analysis and ambient noise deconvolution interferometry for structural and damage identification in historic masonry structures: three case studies of Italian architectural heritage

2019 ◽  
Vol 19 (4) ◽  
pp. 1250-1272 ◽  
Author(s):  
Enrique García-Macías ◽  
Alban Kita ◽  
Filippo Ubertini
Keyword(s):  
Modal Analysis ◽  
Case Studies ◽  
Ambient Noise ◽  
Damage Identification ◽  
Operational Modal Analysis ◽  
Bell Tower ◽  
Wave Velocities ◽  
Historic Structures ◽  
Deconvolution Interferometry

Conservation techniques within the framework of structural health monitoring, particularly through dynamic measurements and operational modal analysis, are becoming popular for condition-based maintenance and decision-making in historic structures. Nonetheless, while effective for giving insight into the overall behaviour of structures, these techniques may fail at detecting local damages with limited effects on the modal features of the system. In this regard, the analysis of propagating waves throughout the structure poses an attractive alternative for data-driven damage identification. Specifically, some encouraging results have been reported on the application of seismic interferometry to reinforced concrete structures, albeit the number of works concerning ambient vibrations is far scarce, and practically nonexistent in the realm of historic structures. In this light, this article explores the synergistic application of operational modal analysis and ambient noise deconvolution interferometry for the structural identification of historic structures through three different case studies, namely the Sciri Tower in Perugia, the Consoli Palace in Gubbio and the bell-tower of the Basilica of San Pietro in Perugia. The first case study represents a typical example of a masonry tower inserted into a building aggregate, while the second one constitutes a particular case of a monumental masonry palace. The presented results and discussion cover diverse aspects of the identification of wave velocities, signal processing strategies, effects of dispersion and robustness of the identification. Finally, the case study of the bell-tower of the Basilica of San Pietro illustrates the application of operational modal analysis and deconvolution interferometry for damage identification. To do so, two different ambient vibration tests conducted before and after the 2016 Central Italy seismic sequence are studied. The results show concentrated reductions in the wave velocities in the area of the belfry, which demonstrates that deconvolution interferometry constitutes a complementary technique to operational modal analysis for damage localization and, to some extent, damage quantification.

Probabilistic analyses of structural dynamic response with modified Kriging-based moving extremum framework

2021 ◽  
Vol 125 ◽  
pp. 105398
Author(s):  
Cheng Lu ◽  
Cheng-Wei Fei ◽  
Yun-Wen Feng ◽  
Yong-Jun Zhao ◽  
Xiao-Wei Dong ◽  
...  
Keyword(s):  
Dynamic Response ◽  
Structural Dynamic

Theoretical and Numerical Analysis on the Seismic Response of Underground Structures in Existence of Isolators

2011 ◽  
Vol 368-373 ◽  
pp. 710-714
Author(s):  
Jin Chun Liu ◽  
Yi Huan
Keyword(s):  
Dynamic Response ◽  
Analytical Procedure ◽  
Axial Loading ◽  
Seismic Loading ◽  
Underground Structures ◽  
Structural Dynamic ◽  
Metro Station ◽  
Single Degree Of Freedom ◽  
Theoretical And Numerical Analysis ◽  
Elastically Supported

In this paper, an analytical method of the beam with springs and dampers fixed at the ends was proposed based on equivalent single degree of freedom (SDOF) system and secondary Lagrange’s dynamic equations, in order to develop a new effective method to enhance the aseismic capability of underground structures. The dynamic response of elastically supported and damply supported beams subjected to both seismic loading and static axial loading was analyzed by the proposed analytical procedure. The theoretical results were validated by the numerical simulation. In order to further investigate the effects of springs and dampers fixed at the ends of the columns in nonlinear response situation, the 3D nonlinear seismic responses of the Dakai metro station structure with and without the isolators were analyzed by ABAQUS respectively. It is demonstrated that: (1) the proposed analytical procedure can predict the dynamic response of beams with elastic and damper supports subjected to both seismic loading and axial loading. (2) Setting isolators at the supports of the column could enhance the aseismic capability of the structure effectively. (3) The axial static loading induced by the gravity of the soil and structure provide the constraint on the column, and therefore could not be neglected in the structural dynamic analysis.

Dynamics Analysis of Refrigeration Compressor Based on Finite Element and Experimental Modes

2012 ◽  
Vol 499 ◽  
pp. 238-242
Author(s):  
Li Zhang ◽  
Hong Wu ◽  
Yan Jue Gong ◽  
Shuo Zhang
Keyword(s):  
Finite Element ◽  
Dynamic Response ◽  
Modal Analysis ◽  
Natural Frequency ◽  
High Precision ◽  
3D Model ◽  
Finite Element Models ◽  
Dynamics Analysis ◽  
Response Characteristics ◽  
Dynamic Response Characteristics

Based on the 3D model of refrigeration's compressor by Pro/E software, the analyses of theoretical and experimental mode are carried out in this paper. The results show that the finite element models of compressor have high precision dynamic response characteristics and the natural frequency of the compressor, based on experimental modal analysis, can be accurately obtained, which will contribute to further dynamic designs of mechanical structures.

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