The Study on Experimental Modal Analysis of High-Speed Rotational Shaft

2012 ◽  
Vol 605-607 ◽  
pp. 1253-1256
Author(s):  
Jun Zhao ◽  
Jian Chang Yuan
Keyword(s):  
Modal Analysis ◽  
High Speed ◽  
Excitation Frequency ◽  
Dominant Frequency ◽  
Experimental Modal Analysis ◽  
Vibration Modes ◽  
Response Signal ◽  
Modal Frequency ◽  
Frequency Components ◽  
Vibration Problems

Centering on the chuck shaft vibration problems in high speed operation of the high-speed winder, experimental modal analysis was used to identify the modal frequency and vibration modes of the chuck shaft different cross-section in the constraint, found out the sensitive point of the response signal ,and the excitation point was found by Relationship between the modal frequency and the input excitation frequency, the results show determined dominant frequency components in the response signal can provide a reliable basis for determining the vibration characteristics of the chuck shaft, analysis of distinguishing the output response signal and selecting response signal point.

The Use of Modan 3D in Experimental Modal Analysis

2013 ◽  
Vol 486 ◽  
pp. 36-41 ◽  
Author(s):  
Róbert Huňady ◽  
František Trebuňa ◽  
Martin Hagara ◽  
Martin Schrötter
Keyword(s):  
Modal Analysis ◽  
Vibration Analysis ◽  
High Speed ◽  
Mechanical Vibration ◽  
Steel Sample ◽  
Experimental Modal Analysis ◽  
Image Correlation ◽  
Optical Methods ◽  
Mode Shapes ◽  
Vibration Modes

Experimental modal analysis is a relatively young part of dynamics, which deals with the vibration modes identification of machines or their parts. Its development has started since the beginning of the eighties, when the computers hardware equipment has improved and the fast Fourier transform (FFT) could be used for the results determination. Nowadays it provides an uncountable set of vibration analysis possibilities starting with conventional contact transducers of acceleration and ending with modern noncontact optical methods. In this contribution we mention the use of high-speed digital image correlation by experimental determination of mode shapes and modal frequencies. The aim of our work is to create a program application called Modan 3D enabling the performing of experimental modal analysis and operational modal analysis. In this paper the experimental modal analysis of a thin steel sample performed with Q-450 Dantec Dynamics is described. In Modan 3D the experiment data were processed and the vibration modes were determined. The reached results were verified by PULSE modulus specialized for mechanical vibration analysis.

Vibration Modal Analysis of the Full-Sized Medium Density Fiberboard

2014 ◽  
Vol 620 ◽  
pp. 268-273 ◽  
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.

The local extinction and the nonlinear behaviors of a premixed methane/air flame under low-frequency acoustic excitation

2020 ◽  
Vol 34 (13) ◽  
pp. 2050138 ◽  
Author(s):  
Yongchao Sun ◽  
Mingbo Sun ◽  
Jiajian Zhu ◽  
Yang Xie ◽  
Hongbo Wang ◽  
...  
Keyword(s):  
High Speed ◽  
Excitation Frequency ◽  
Dominant Frequency ◽  
Local Extinction ◽  
Acoustic Excitation ◽  
Flame Extinction ◽  
Buoyant Force ◽  
Hot Gas ◽  
Nature Frequency ◽  
Production Zone

The local extinction and the nonlinear behavior of a premixed methane/air flame under acoustic excitation are investigated experimentally. High-speed photography and high-speed schlieren imaging are used to investigate the oscillation characteristics of the premixed methane/air flame. The flame structure shows a periodic fluctuation when the acoustic excitation is performed to the flame. The local flame extinction can be observed during the flame evolution process. During the local flame extinction process, the flame is found to be cut into two components, then the downstream one extinguishes shortly. The Particle Image Velocimetry (PIV) results suggest that the lower velocity at the separation point is one of the reasons for the flame local extinction. The flame without the acoustic excitation oscillates with a dominant frequency of 18 Hz, which is shown by the schlieren images to be related to the evolution of the hot gas around the flame driven by the buoyant force. When the acoustic excitation frequency is 100 Hz, the structure of the hot gas is destroyed, meanwhile the amplitude of the nature frequency decreases significantly. The hot gas structure appears regularly with the increasing excitation frequency. As a result, the amplitude of the nature frequency also increases gradually. Proper Orthogonal Decomposition (POD) analysis shows that the dominant frequency of the flame without the acoustic excitation is mainly caused by the evolution of the production zone of the flame and the fluctuation of the flame tip. The evolution of the production zone is driven by the buoyant force, which indicates that the result from POD method is consistent with the conclusion obtained from the high-speed schlieren images. Two dominant modes are obtained when the excitation frequencies are 100 and 200 Hz. The two modes are mainly caused by the process of the local flame extinction and the increasing flame length.

Application of Experimental Modal Analysis Method in Researching of Mechanical Structure Dynamic Characteristics

2013 ◽  
Vol 694-697 ◽  
pp. 370-373
Author(s):  
Zhang Yu ◽  
Wen Zheng Cai
Keyword(s):  
Modal Analysis ◽  
Natural Frequency ◽  
Dynamic Characteristics ◽  
High Speed ◽  
Experimental Modal Analysis ◽  
Analysis Method ◽  
Mechanical Structure ◽  
Vibration Resistance ◽  
Structural Rigidity ◽  
Structure Dynamic

With the purpose of realizing the analysis of mechanical structure dynamic characteristics and inhibit vibration and noise, combined with the analysis of a certain type of high speed sewing machines vibration characteristics, we carry on the concrete experimental modal analysis, and compare the results of the experimental modal analysis with the results of spectrum analysis. The analysis results show that the second order natural frequency of the shell is close to two octaves under the normal working speed of sewing machine and it will lead to resonance. Enhancing the structural rigidity and the natural frequency under this modal to avoid resonance frequency is the key to improve vibration resistance of the structure.

scholarly journals Experimental modal analysis in research

2017 ◽  
Vol 16 (3) ◽  
pp. 005-012 ◽  
Author(s):  
Mariusz Żółtowski ◽  
Krzysztof Napieraj
Keyword(s):  
Parameter Estimation ◽  
Modal Analysis ◽  
Civil Engineering ◽  
Experimental Modal Analysis ◽  
Impact Testing ◽  
Engineering Industry ◽  
Vibration Modes ◽  
Modal Parameter ◽  
Excitation Techniques ◽  
Modal Parameter Estimation

Experimental modal analysis has grown steadily in popularity since the advent of the digital FFT spectrum analyser in the 1970’s. This days impact testing has become widespread as a fast and economical means of finding the vibration modes of a machine or structure. Its significantly use ascending roles can be seen also in the civil engineering industry [6]. This paper reviews the main topics associated with experimental modal analysis including making FRF measurements, modal excitation techniques, and modal parameter estimation from a set of FRFs.

Application of Statistical Methods in Experimental Modal Frequency Extraction

2015 ◽  
Vol 738-739 ◽  
pp. 569-572
Author(s):  
Jian Wei Jiang ◽  
De Jian Zhou ◽  
Bing Li ◽  
Yu Tang ◽  
Xiang Yang Xie
Keyword(s):  
Mathematical Method ◽  
Modal Analysis ◽  
Statistical Methods ◽  
Experimental Modal Analysis ◽  
General Analysis ◽  
Excitation Source ◽  
Modal Frequency ◽  
Statistical Frequency

In order to extract the experimental modal analysis of the Modal frequency accurately, measuring twelve set of data during the experiment, to use the method of statistical frequency based on mathematical method to extract modal frequencies. It is helpful to avoid frequency leakage phenomenon as the reasons of excitation source select inappropriate and quickly and efficiently for a general analysis staff to extract the modal frequency values.

High-Speed Camera based Experimental Modal Analysis for Dynamic Testing of an Automotive Coil Spring

2021 ◽  
Author(s):  
Felix Simeon Egner ◽  
Yonggang Wang ◽  
Thijs Willems ◽  
Matteo Kirchner ◽  
Bert Pluymers ◽  
...  
Keyword(s):  
Modal Analysis ◽  
High Speed ◽  
Dynamic Testing ◽  
Experimental Modal Analysis ◽  
High Speed Camera ◽  
Coil Spring

Modal Analysis on a High Speed Train Based on Forced Excitation From Track

2012 ◽  
Author(s):  
Lara Ma Erviti Calvo ◽  
Gorka Agirre Castellanos ◽  
Igor Alonso Portillo ◽  
Mayi Garcia Prada
Keyword(s):  
Modal Analysis ◽  
High Speed ◽  
Impact Force ◽  
Impact Excitation ◽  
Modal Parameters ◽  
Maximum Speed ◽  
Vibration Modes ◽  
Test Results ◽  
High Speed Train ◽  
Railway Vehicles

The more demanding safety and comfort requirements combined with the increasing maximum speed of trains have lead to a growing concern in aspects such as the determination of the modal parameters of railway vehicles. Until now, the modal parameters of a vehicle have been obtained by EMA (Experimental Modal Analysis) based on the application of an impact force on the vehicle frame. However this kind of test is not optimal for railway vehicles because, due to their large dimensions, an impact force is unable to excite all the points of the structure. Also, with this method only the structural modes can be analyzed. Because of these drawbacks, a new modal analysis methodology is proposed, in which the excitation force comes from a specially designed shaker mounted under a point of a test track. In this manner, real excitation conditions can be simulated and it allows to determine not only the structural modes, but also the vibration modes associated with the suspensions. In first place, a description of the test facilities is presented. Afterwards, we present a test carried out in one of the coaches of a high speed train. The instrumentation employed, test methodology and test results are described. Finally, the test results are compared with the results obtained from a modal test in which impact excitation was used. Also the vibration modes obtained in the test are compared with the theoretical ones, which have been calculated with a combination of a FEM (Finite Element Method) and a MBS (Multi-Body Simulation).

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