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

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.

2012 ◽  
Vol 605-607 ◽  
pp. 1253-1256
Author(s):  
Jun Zhao ◽  
Jian Chang Yuan

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.


2014 ◽  
Vol 620 ◽  
pp. 268-273 ◽  
Author(s):  
Cheng Guan ◽  
Lu Jing Zhou ◽  
Hou Jiang Zhang ◽  
Kang Hua Li

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.


2015 ◽  
Vol 39 (1) ◽  
pp. 145-149 ◽  
Author(s):  
Ewa B. Skrodzka ◽  
Bogumił B.J. Linde ◽  
Antoni Krupa

Abstract Experimental modal analysis of a violin with three different tensions of a bass bar has been performed. The bass bar tension is the only intentionally introduced modification of the instrument. The aim of the study was to find differences and similarities between top plate modal parameters determined by a bass bar perfectly fitting the shape of the top plate, the bass bar with a tension usually applied by luthiers (normal), and the tension higher than the normal value. In the modal analysis four signature modes are taken into account. Bass bar tension does not change the sequence of mode shapes. Changes in modal damping are insignificant. An increase in bass bar tension causes an increase in modal frequencies A0 and B(1+) and does not change the frequencies of modes CBR and B(1-).


2013 ◽  
Vol 486 ◽  
pp. 36-41 ◽  
Author(s):  
Róbert Huňady ◽  
František Trebuňa ◽  
Martin Hagara ◽  
Martin Schrötter

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.


Author(s):  
Bekir AKTAŞ ◽  
Ferhat ÇEÇEN ◽  
Hakan ÖZTÜRK ◽  
Burhan M. NAVDAR ◽  
İrfan Ş. ÖZTÜRK

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