Vibration of Press Based on Operational Modal Analysis

Press vibration characteristic is the basic of press fault diagnosis and static optimization. We get press vibration characteristics with Operational Modal Analysis .Comparing theoretical analysis of the finite element method for press with operation modal analysis of test method for press in the actual condition. We get vibration modal orders and vibration modes of press wallboard under natural excitation. The experimental results show that the test modal frequency identification value of Operational Modal Analysis for the press components is highly accurate.

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Component Mode Synthesis Method Applied to Acoustic Resonators in Ducts for Structural Vibration Analysis

10.20855/ijav.2020.25.41638 ◽

2020 ◽

Vol 25 (4) ◽

pp. 498-503

Author(s):

Jose Manuel Bautista Ordóñez ◽

Maria Alzira de Araújo Nunes

Keyword(s):

Finite Element Method ◽

Finite Element ◽

Modal Analysis ◽

Natural Frequencies ◽

Component Mode Synthesis ◽

Structural Vibration ◽

Structural Systems ◽

Vibration Modes ◽

The Finite Element Method ◽

Element Method

Tubular structural systems appear in many industrial applications, such as heating, ventilation, and air conditioning systems, which are responsible for making any enclosed environment remain within a temperature, humidity, and cleanliness range. This kind of system has its applications in the internal environmental comfort of industrial spaces, buildings, and vehicles. Several of these spaces have industrial processes that generate high sound frequencies and mechanical vibrations that need to be adequately controlled to meet both environmental and health norms. With the intention to analyze the structural vibration of tubular systems, the modal analysis technique is a classical methodology for the extraction of natural frequencies and vibration modes. Among the various techniques of modal analysis, numerical methodologies such as the finite element method, and also analytical methodologies such as the Component Mode Synthesis (CMS) can be found. CMS is one of the leading modeling tools for complex systems that are applied to large systems. The method uses a modal superset and consists of separately modeling individual components of a structure and coupling them into a single system. The objective of this work is to demonstrate the application of the CMS technique through the estimation of natural frequencies and vibration modes in a simplified tubular structural system formed by two substructures, using MATLAB and ANSYS. The validation of the results was done through numerical modeling using the finite element method using and ANSYS software. The results obtained were satisfactory, thus demonstrating the feasibility of applying the CMS technique to an analysis of structural vibration in tubular structural systems.

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Modal Analysis Of Blended Wing-Body UAV

Jurnal Teknologi Kedirgantaraan ◽

10.35894/jtk.v6i2.39 ◽

2021 ◽

Vol 6 (2) ◽

pp. 68-75

Author(s):

Neno Ruseno

Keyword(s):

Modal Analysis ◽

Leading Edge ◽

Comsol Multiphysics ◽

Vibration Characteristic ◽

The Finite Element Method ◽

Horizontal Movement ◽

Aerial Vehicle ◽

Eigen Frequencies ◽

Blended Wing Body ◽

The Difference

The modal analysis deals with the dynamic behavior of mechanical structures under the dynamic vibration. This study aims to analyze the vibration characteristic of the blended wing-body Unmanned Aerial Vehicle (UAV) using modal analysis. The numerical method is used to calculate the eigen frequencies of the system. The COMSOL Multiphysics is selected as the Finite Element Method (FEM) software to simulate the study. The resulted eigen frequencies are 278.05 Hz, 721.28 Hz, 816.39 Hz, 1601.7 Hz, 1699.5 Hz, and 1855.5 Hz. The study also evaluates the displacement of the leading edge of the wing in all axes to understand the modal shapes. The modal shapes found are updrift, swift back, flapping vertical, flapping horizontal, flapping opposite horizontal and flapping more wave in horizontal movement. The comparison of resulted eigen frequencies with a conventional aircraft wing is conducted to understand the difference in its vibration characteristics.

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Effect of Vinyl Flooring on the Modal Properties of a Steel Footbridge

Applied Sciences ◽

10.3390/app9071374 ◽

2019 ◽

Vol 9 (7) ◽

pp. 1374 ◽

Cited By ~ 3

Author(s):

Javier Jiménez-Alonso ◽

Jorge Pérez-Aracil ◽

Alejandro Hernández Díaz ◽

Andrés Sáez

Keyword(s):

Modal Analysis ◽

Operational Modal Analysis ◽

Modal Parameters ◽

Vibration Modes ◽

Structural Elements ◽

Average Increase ◽

Analysis Method ◽

Structural Element ◽

Modal Properties

Damping ratios associated with non-structural elements play an important role in mitigating the pedestrian-induced vibrations of slender footbridges. In particular, this paper analyses the effect of vinyl flooring on the modal parameters of steel footbridges. Motivated by the unexpected high experimental damping ratios of the first vibration modes of a real footbridge, whose deck was covered by a vinyl flooring, this paper aims at assessing more accurately the experimental damping ratios generated by this non-structural element on steel footbridges. For this purpose, a laboratory footbridge was built and vinyl flooring was installed on it. Its numerical and experimental modal parameters without and with the vinyl flooring were determined. The operational modal analysis method was used to estimate experimentally the modal parameters of the structure. The damping ratios associated with the vinyl flooring were obtained via the substraction between the experimental damping ratios of the laboratory footbridge with and without the vinyl flooring. An average increase of the damping ratios of 2.069% was observed due to the vinyl flooring installed. According to this result, this type of pavement may be a useful tool to significantly increase the damping ratios of steel footbridges in order to reduce pedestrian-induced vibrations.

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Modal Analysis of Laminated “CAS” and “CUS” Box-Beams

Archive of Mechanical Engineering ◽

10.1515/meceng-2017-0026 ◽

2017 ◽

Vol 64 (4) ◽

pp. 441-454 ◽

Cited By ~ 4

Author(s):

Jarosław Gawryluk ◽

Marcin Bocheński ◽

Andrzej Teter

Keyword(s):

Modal Analysis ◽

Mode Coupling ◽

Composite Structures ◽

Vibration Mode ◽

Coupling Effect ◽

Experimental Modal Analysis ◽

Vibration Modes ◽

The Finite Element Method ◽

Numerical Studies ◽

Box Beams

Abstract In the paper, the authors discuss the numerical and experimental modal analysis of the cantilever thin-walled beams made of a carbon-epoxy laminate. Two types of beams were considered: circumferentially asymmetric stiffness (i.e., CAS) and circumferentially uniform stiffness (i.e., CUS) beams. The layer-up configurations of the laminate were chosen to get a vibration mode coupling effect in both analysed cases. The aim of the paper was to perform the numerical and experimental modal analysis of the composite structures, when a flapwise bending with torsion coupling effect or flapwise-chordwise bending coupling effect took place. Firstly, numerical studies by the finite element method was performed. The numerical simulations were carried out by the Lanczos method in the Abaqus software package. The natural frequencies and the corresponding free vibration modes were determined. Next, the experimental modal analyses of the CAS and CUS beams were performed. The test stand was consisted of a special grip, two beams with an adhered holder, the LMS Scadas III system with a modal hammer and an acceleration sensor. Finally, the results of both methods were compared.

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Vibration Modal Analysis of the Full-Sized Medium Density Fiberboard

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.620.268 ◽

2014 ◽

Vol 620 ◽

pp. 268-273 ◽

Cited By ~ 2

Author(s):

Cheng Guan ◽

Lu Jing Zhou ◽

Hou Jiang Zhang ◽

Kang Hua Li

Keyword(s):

Modal Analysis ◽

Medium Density Fiberboard ◽

Experimental Modal Analysis ◽

Vibration Modes ◽

Medium Density ◽

Bending Vibration ◽

Modal Frequency ◽

Width Direction ◽

Length Direction ◽

Vibration Modal

To determine modulus of elasticity (MOE) of the whole full-sized medium density fiberboard (MDF) by using vibration method in the future, this paper studies MDF vibration characteristics. To solve modal parameters of full-sized MDF in the condition of free vibration, the writers conducted calculation modal analysis and experimental modal analysis of the full-sized MDF with three different thicknesses respectively, compared and analyzed the first three order modal shapes and frequencies. It is found that the full-sized MDF with three different thicknesses showed the same vibration modal forms: the first and second vibration modes had bending vibration along the length direction, while the third one had bending vibration along the width direction; the frequency obtained through calculation modal analysis and experimental modal analysis had a certain difference—the first calculation modal frequency was slightly lower than the first experimental modal frequency, and the second and third calculation modal frequencies higher than the corresponding experimental modal frequencies. However, there is a good correlation between calculation modal frequency and test experimental modal frequency with the determination coefficient reaching 0.9816.

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Response and Operational Modal Analysis from Wind Tunnel Test of the EOLO Flexible Aircraft

AIAA Scitech 2021 Forum ◽

10.2514/6.2021-1389 ◽

2021 ◽

Author(s):

David F. Castillo Zuñiga ◽

Alain Giacobini Souza ◽

Roberto G. da Silva ◽

Luiz Carlos Sandoval Góes

Keyword(s):

Wind Tunnel ◽

Modal Analysis ◽

Wind Tunnel Test ◽

Operational Modal Analysis ◽

Flexible Aircraft

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Comparison of response transmissibility and power spectral density transmissibility on operational modal analysis

Mechanical Systems and Signal Processing ◽

10.1016/j.ymssp.2021.107912 ◽

2021 ◽

Vol 160 ◽

pp. 107912

Author(s):

Jie Kang ◽

Hehua Ju ◽

Li Liu

Keyword(s):

Spectral Density ◽

Modal Analysis ◽

Power Spectral Density ◽

Operational Modal Analysis ◽

Power Spectral

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

Sensors ◽

10.3390/s21051602 ◽

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.

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