Full structural dynamic response from ambient vibration of Giotto's bell tower in Firenze (Italy), using modal analysis and seismic interferometry

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.

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

Engineering Failure Analysis ◽

10.1016/j.engfailanal.2021.105398 ◽

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

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High precision videogrammetric technique for structural dynamic response measurement

10.1117/12.599320 ◽

2005 ◽

Author(s):

Chih-Chen Chang ◽

Yunfeng Ji

Keyword(s):

Dynamic Response ◽

High Precision ◽

Response Measurement ◽

Structural Dynamic

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Study on dynamic response characteristics of high and steep layered rock mass slopes using a modal analysis method

IOP Conference Series Earth and Environmental Science ◽

10.1088/1755-1315/570/6/062013 ◽

2020 ◽

Vol 570 ◽

pp. 062013

Author(s):

D Q Song ◽

J Huang ◽

X L Liu ◽

E Z Wang ◽

J M Zhang

Keyword(s):

Rock Mass ◽

Dynamic Response ◽

Modal Analysis ◽

Analysis Method ◽

Response Characteristics ◽

Layered Rock ◽

Layered Rock Mass ◽

Dynamic Response Characteristics ◽

Rock Mass Slopes

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

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.368-373.710 ◽

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.

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

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.499.238 ◽

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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Stochastic Dynamic Analysis of Structures with Spatially Uncertain Material Parameters

International Journal of Structural Stability and Dynamics ◽

10.1142/s021945541440029x ◽

2014 ◽

Vol 14 (08) ◽

pp. 1440029 ◽

Cited By ~ 6

Author(s):

Kheirollah Sepahvand ◽

Steffen Marburg

Keyword(s):

Finite Element ◽

Modal Analysis ◽

Polynomial Chaos ◽

Element Model ◽

Stochastic Dynamic ◽

Stochastic Field ◽

Structural Dynamic ◽

Material Parameters ◽

Material Uncertainties ◽

Stochastic Dynamic Analysis

This paper investigates the uncertainty quantification in structural dynamic problems with spatially random variation in material and damping parameters. Uncertain and locally varying material parameters are represented as stochastic field by means of the Karhunen–Loève (KL) expansion. The stiffness and damping properties of the structure are considered uncertain. Stochastic finite element of structural modal analysis is performed in which modal responses are represented using the generalized polynomial chaos (gPC) expansion. Knowing the KL expansions of the random parameters, the nonintrusive technique is employed on a set of random collocation points where the structure deterministic finite element model is executed to estimate the unknown coefficients of the polynomial chaos expansions. A numerical case study is presented for a cantilever beam with random Young's modulus involving spatial variation. The proportional damping constants are estimated from the experimental modal analysis. The expected value, standard deviation, and probability distribution of the random eigenfrequencies and the damping ratios are evaluated. The results show high accuracy compared to the Monte-Carlo (MC) simulations with 3000 realizations. It is also demonstrated that the eigenfrequencies and the damping ratios are equally affected from material uncertainties.

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