Validation of a modal identification procedure for linear frames under unmeasured seismic input

2014 ◽  
Author(s):  
Vincenzo Sepe ◽  
Rossella Siano ◽  
Fabrizio Iezzi ◽  
Claudio Valente
Keyword(s):  
Modal Identification ◽  
Identification Procedure ◽  
Seismic Input

scholarly journals Online Modal Identification of Concrete Dams Using the Subspace Tracking-Based Method

2019 ◽  
Vol 2019 ◽  
pp. 1-18 ◽  
Author(s):  
Lin Cheng ◽  
Fei Tong ◽  
Jie Yang ◽  
Dongjian Zheng
Keyword(s):  
Strong Motion ◽  
Arch Dam ◽  
Modal Identification ◽  
Subspace Identification ◽  
Time Varying ◽  
Subspace Tracking ◽  
Concrete Dams ◽  
Identification Procedure ◽  
Strong Motion Records ◽  
Stochastic Subspace Identification

To investigate the time-varying dynamic characteristics of concrete dams under the excitation of large earthquakes for online structural health monitoring and damage evaluation, an online modal identification procedure based on strong-motion records is proposed. The online modal identification of concrete dams is expressed as a subspace tracking problem, and a newly developed recursive stochastic subspace identification (RSSI) method based on the generalized yet another subspace tracker (GYAST) algorithm, which exploits both the accuracy of the subspace identification and fast computational capability, is used to extract the time-varying modal parameters of concrete dams during earthquakes. With the simulated vibration response records, a numerical example is used to verify the accuracy, robustness, and efficiency of the proposed GYAST-based, time-varying modal identification method. Then, the realistic strong-motion records of the Pacoima arch dam are analysed using the proposed modal identification procedure, and the time-varying characteristics of the concrete arch dam during three different earthquakes are analysed.

Modal Identification of Multi-Degree-of-Freedom Mechanical Systems Endowed With Geometric Nonlinearities

2005 ◽  
Author(s):  
R. Camillacci ◽  
C. Valente ◽  
F. Brancaleoni
Keyword(s):  
Mechanical Characteristics ◽  
Modal Identification ◽  
Laboratory System ◽  
Identification Procedure ◽  
Functional Relationships ◽  
Linear Behavior ◽  
Physical Laboratory ◽  
Set Up ◽  
Free Vibration Response ◽  
Different Levels

An identification procedure for a sample class of mechanical system exhibiting non-linear behavior is presented and validated experimentally. The proposed procedure operates on the free-vibration response of the system and is able not only to extract the time-depended modal parameters, but also to identify the functional relationships between modal frequencies and modal amplitudes of oscillation. These relationships depend just on the mechanical characteristics of the system and thus, they characterize entirely the dynamic behavior. An experimental validation of the procedure performed on a physical laboratory system is presented and discussed. The experimental set-up was designed in order to allow for different configurations and hence for different levels of nonlinearity. The comparison between the identified results and the results of a proper analytical model of the system allows for highlighting the sensibility and effectiveness of the proposed procedure.

THE MODAL IDENTIFICATION METHOD IN NONLINEAR HEAT TRANSFER PROBLEMS

Equipment ◽  
2006 ◽  
Author(s):  
O. Balima ◽  
D. Petit ◽  
J. B. Saulnier ◽  
M. Girault ◽  
Y. Favennec
Keyword(s):  
Heat Transfer ◽  
Modal Identification ◽  
Identification Method ◽  
Nonlinear Heat Transfer ◽  
Transfer Problems

Application of Quaternion Numbers in Identification Scheme

2015 ◽  
Vol 3 (2) ◽  
Author(s):  
Reza Alimoradi
Keyword(s):  
Access Control ◽  
Control Methods ◽  
Identification Procedure ◽  
Identification Scheme

The goal of an identification procedure is access control. Methods that permit an identification are called identification protocols. In this paper, first we introduced quaternion numbers. In addition we proposed a new identification scheme based on quaternions. Finally, the security of our scheme is analyzed.

scholarly journals Consistent cross-modal identification of cortical neurons with coupled autoencoders

2021 ◽  
Vol 1 (2) ◽  
pp. 120-127
Author(s):  
Rohan Gala ◽  
Agata Budzillo ◽  
Fahimeh Baftizadeh ◽  
Jeremy Miller ◽  
Nathan Gouwens ◽  
...  
Keyword(s):  
Cortical Neurons ◽  
Modal Identification

Modal characteristics and fluid–structure interaction vibration response of submerged impeller

2021 ◽  
pp. 107754632110036
Author(s):  
Shihui Huo ◽  
Hong Huang ◽  
Daoqiong Huang ◽  
Zhanyi Liu ◽  
Hui Chen
Keyword(s):  
Flow Field ◽  
Unsteady Flow ◽  
Damping Ratio ◽  
Pure Water ◽  
Vibration Response ◽  
Modal Identification ◽  
Liquid Oxygen ◽  
Modal Characteristics ◽  
Oxygen Pump ◽  
Turbo Pump

Turbo pump is one of the elements with the most complex flow of liquid rocket engine, and as an important component of turbo pump, an impeller is the weak point affecting its reliability. In this study, a noncontact modal characteristic identification technique was proposed for the liquid oxygen pump impeller. Modal characteristics of the impeller under three different submerged media, air, pure water, and brine with same density as liquid oxygen, were tested based on the noncontact modal identification technology. Submersion state directly affects the modal frequencies and damping ratio. The transient vibration response characteristics of the impeller excited by the unsteady flow field was achieved combining with unsteady flow field analysis and transient dynamic analysis in the whole flow passage of the liquid oxygen pump. Vibration responses at different positions of the impeller show 10X and 20X frequencies, and the amplitude at the root of short blade is significant, which needs to be paid more attention in structural design and fatigue evaluation.

Modal identification of concrete arch dam by fully automated operational modal identification

Structures ◽  
2021 ◽  
Vol 32 ◽  
pp. 228-236
Author(s):  
Hasan Mostafaei ◽  
Mehdi Ghamami ◽  
Pegah Aghabozorgi
Keyword(s):  
Arch Dam ◽  
Modal Identification ◽  
Concrete Arch Dam
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