An Extended Karhunen-Loève Decomposition for Modal Identification of Inhomogeneous Structures

2006 ◽  
Vol 128 (3) ◽  
pp. 357 ◽  
Author(s):  
U. Iemma ◽  
M. Diez ◽  
L. Morino
Keyword(s):  
Modal Identification

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

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

scholarly journals Full-Field Operational Modal Analysis of an Aircraft Composite Panel from the Dynamic Response in Multi-Impact Test

Sensors ◽  
2021 ◽  
Vol 21 (5) ◽  
pp. 1602
Author(s):  
Ángel Molina-Viedma ◽  
Elías López-Alba ◽  
Luis Felipe-Sesé ◽  
Francisco Díaz
Keyword(s):  
Modal Analysis ◽  
Energy Absorption ◽  
High Speed ◽  
Operational Modal Analysis ◽  
Modal Identification ◽  
Image Correlation ◽  
Composite Panel ◽  
Impact Excitation ◽  
Full Field ◽  
The Impact

Experimental characterization and validation of skin components in aircraft entails multiple evaluations (structural, aerodynamic, acoustic, etc.) and expensive campaigns. They require different rigs and equipment to perform the necessary tests. Two of the main dynamic characterizations include the energy absorption under impact forcing and the identification of modal parameters through the vibration response under any broadband excitation, which also includes impacts. This work exploits the response of a stiffened aircraft composite panel submitted to a multi-impact excitation, which is intended for impact and energy absorption analysis. Based on the high stiffness of composite materials, the study worked under the assumption that the global response to the multi-impact excitation is linear with small strains, neglecting the nonlinear behavior produced by local damage generation. Then, modal identification could be performed. The vibration after the impact was measured by high-speed 3D digital image correlation and employed for full-field operational modal analysis. Multiple modes were characterized in a wide spectrum, exploiting the advantages of the full-field noninvasive techniques. These results described a consistent modal behavior of the panel along with good indicators of mode separation given by the auto modal assurance criterion (Auto-MAC). Hence, it illustrates the possibility of performing these dynamic characterizations in a single test, offering additional information while reducing time and investment during the validation of these structures.

scholarly journals An Underdetermined Blind Source Separation Method with Application to Modal Identification

2019 ◽  
Vol 2019 ◽  
pp. 1-15 ◽  
Author(s):  
Gang Yu
Keyword(s):  
Blind Source Separation ◽  
Source Separation ◽  
Modal Identification ◽  
Modal Parameters ◽  
Underdetermined Blind Source Separation ◽  
Structural Dynamic ◽  
Time Frequency ◽  
Modal Response ◽  
Experimental Validations ◽  
Straight Lines

In structural dynamic analysis, the blind source separation (BSS) technique has been accepted as one of the most effective ways for modal identification, in which how to extract the modal parameters using very limited sensors is a highly challenging task in this field. In this paper, we first review the drawbacks of the conventional BSS methods and then propose a novel underdetermined BSS method for addressing the modal identification with limited sensors. The proposed method is established on the clustering features of time-frequency (TF) transform of modal response signals. This study finds that the TF energy belonging to different monotone modals can cluster into distinct straight lines. Meanwhile, we provide the detailed theorem to explain the clustering features. Moreover, the TF coefficients of each modal are employed to reconstruct all monotone signals, which can benefit to individually identify the modal parameters. In experimental validations, two experimental validations demonstrate the effectiveness of the proposed method.

Full-scale dynamic testing and modal identification of a coupled floor slab system

2012 ◽  
Vol 37 ◽  
pp. 167-178 ◽  
Author(s):  
S.K. Au ◽  
Y.C. Ni ◽  
F.L. Zhang ◽  
H.F. Lam
Keyword(s):  
Dynamic Testing ◽  
Full Scale ◽  
Modal Identification ◽  
Floor Slab

Robust modal identification/estimation of the Mini-Mast testbed

1992 ◽  
Vol 15 (3) ◽  
pp. 642-647 ◽  
Author(s):  
Michael J. Roemer ◽  
D. Joseph Mook
Keyword(s):  
Modal Identification
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