scholarly journals Estimation of natural frequencies of the laboratory truss structure with output only subspace and frequency-domain techniques

2020 ◽  
Vol 313 ◽  
pp. 00003
Author(s):  
Ján Kortiš ◽  
Lukáš Maliar ◽  
Ľuboš Daniel
Keyword(s):  
Modal Analysis ◽  
Natural Frequencies ◽  
Structural Testing ◽  
Truss Structure ◽  
Current State ◽  
Steel Truss ◽  
Output Only ◽  
Frequency Domain Techniques ◽  
Non Destructive ◽  
Destructive Methods

Non-destructive methods of structural testing are preferred to identify their current state because they do not damage the structure. Modal analysis is one of these methods that can be used for a comprehensive assessment of structural measurements. Its main advantage is that it can be used for variety applications. The paper presents an application of operational modal analysis to determine modal parameters of a laboratory steel truss structure. Its goal is to make contribution to the still unfinished development of modal analysis in the area of comprehensive application. There is important to try to use it and especially try to derive some basic generally applicable rules. It is an important step for experimental modal analysis before it can be widely used and accepted in engineering applications.

scholarly journals Operational Modal Analysis of the Laboratory Steel Truss Structure

2019 ◽  
Vol 40 ◽  
pp. 800-807
Author(s):  
Lukáš Maliar ◽  
Daniela Kuchárová ◽  
Ľuboš Daniel
Keyword(s):  
Modal Analysis ◽  
Operational Modal Analysis ◽  
Truss Structure ◽  
Steel Truss

Output-Only Modal Analysis of Micromilling Systems

2017 ◽  
Vol 6 (1) ◽  
Author(s):  
K. Ahmadi
Keyword(s):  
Sensitivity Analysis ◽  
Modal Analysis ◽  
Frequency Response Function ◽  
Natural Frequencies ◽  
Laser Doppler Vibrometer ◽  
Practical Method ◽  
Acoustic Excitation ◽  
Milling Operations ◽  
Noise Input ◽  
Output Only

An output-only modal analysis (OMA) approach is presented to obtain the direct frequency response function (FRF) at the tip of the tool in micromilling setups. White noise input is provided using acoustic excitation and the resulting vibrations are measured using a laser Doppler vibrometer (LDV). Autoregressive (AR) identification is used to extract the natural frequencies and damping ratios of the structural modes of the milling setup, and mass-sensitivity analysis is used to obtain modal stiffness values. The accuracy of the tool tip FRFs that are constructed using OMA is verified by comparing them against the FRFs that are measured using impulse hammer tests. The direct FRF at the tool tip is an essential component in predicting and avoiding excessive and unstable vibrations in milling operations, and the presented approach provides a practical method for the direct measurement of the tool tip FRF in micromilling where the application of traditional hammer tests is not possible.

OUTPUT-ONLY MODAL ANALYSIS OF AN ELECTRICAL SUBMERSIBLE PUMP USING TIME AND FREQUENCY DOMAIN TECHNIQUES

2017 ◽  
Author(s):  
Jairo Alvaro C. Huamani ◽  
Ulisses A. Monteiro ◽  
Ricardo H.R. Gutiérrez ◽  
Antonio Carlos Ramos Troyman ◽  
Luiz A. Vaz
Keyword(s):  
Modal Analysis ◽  
Frequency Domain ◽  
Submersible Pump ◽  
Electrical Submersible Pump ◽  
Output Only ◽  
Frequency Domain Techniques

scholarly journals ASSESSMENT OF THE CURRENT STATE OF THE CONCRETE STRUCTURE OF THE TRIBUNE

2020 ◽  
Vol 12 (2) ◽  
pp. 72-76
Author(s):  
MIROSLAV BRODŇAN ◽  
PETER KOTEŠ
Keyword(s):  
Reinforced Concrete ◽  
Concrete Structure ◽  
Reinforced Concrete Structure ◽  
Complex State ◽  
Load Bearing ◽  
Current State ◽  
Concrete Elements ◽  
Non Destructive ◽  
Destructive Methods

The paper is focused on diagnostics of reinforced concrete structure of the tribune of Závodisko Bratislava. The structure was realized by a combination of monolithic and prefabricated concrete elements as well as steel load-bearing elements. The complex state of the rough construction was evaluated, including the verification survey of the foundation of the construction. Non-destructive and destructive methods were used. Based on the results of the diagnostics and recalculation, it was decided to further progress the finish of the tribune.

Measurement of Young’s Modulus and Shear Modulus of Some Structures Welded Using Flux Cored Wire by Vibration Tests

2014 ◽  
Vol 216 ◽  
pp. 151-156 ◽  
Author(s):  
Liviu Bereteu ◽  
Mircea Vodǎ ◽  
Gheorghe Drăgănescu
Keyword(s):  
Shear Modulus ◽  
Arc Welding ◽  
Natural Frequencies ◽  
Free Vibrations ◽  
Vibration Modes ◽  
Cored Wire ◽  
Flux Cored Arc Welding ◽  
Longitudinal Elastic Modulus ◽  
Vibration Tests ◽  
Non Destructive

The aim of this work was to determine by vibration tests the longitudinal elastic modulus and shear modulus of welded joints by flux cored arc welding. These two material properties are characteristic elastic constants of tensile stress respectively torsion stress and can be determined by several non-destructive methods. One of the latest non-destructive experimental techniques in this field is based on the analysis of the vibratory signal response from the welded sample. An algorithm based on Pronys series method is used for processing the acquired signal due to sample response of free vibrations. By the means of Finite Element Method (FEM), the natural frequencies and modes shapes of the same specimen of carbon steel were determined. These results help to interpret experimental measurements and the vibration modes identification, and Youngs modulus and shear modulus determination.

Rust creep assessment—A comparison between a destructive method according to ISO 12944 and selected non-destructive methods

2021 ◽  
Vol 157 ◽  
pp. 106293
Author(s):  
Huichao Bi ◽  
Claus Erik Weinell ◽  
Raquel Agudo de Pablo ◽  
Benjamín Santos Varela ◽  
Sergio González Carro ◽  
...  
Keyword(s):  
Non Destructive ◽  
Destructive Methods
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