scholarly journals Improvement of Accuracy and Reliability of Experimental Modal Analysis. Invention on Impact Testing and Decreases of Measurement Error.

1998 ◽  
Vol 64 (618) ◽  
pp. 538-545 ◽  
Author(s):  
Mitsuo IWAHARA ◽  
Taei SUGIURA ◽  
Akio NAGAMATSU
Keyword(s):  
Measurement Error ◽  
Modal Analysis ◽  
Experimental Modal Analysis ◽  
Impact Testing

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.

Experimental Modal Analysis of Compressor Vibration Isolating System Based on LMS Test.Lab

2011 ◽  
Vol 121-126 ◽  
pp. 3283-3288
Author(s):  
Li Zhang ◽  
Hao Chen ◽  
Yan Jue Gong ◽  
Jing Wang
Keyword(s):  
Resonance Frequency ◽  
Modal Analysis ◽  
Natural Frequency ◽  
Single Layer ◽  
Experimental Modal Analysis ◽  
Impact Testing ◽  
Modal Parameters ◽  
Isolation System ◽  
Refrigeration Unit ◽  
Comparison Results

In order to reduce vibration and noise of the compressor used in small and medium-sized refrigeration unit, this paper designs different vibration isolating systems and carries out experimental modal analysis based on LMS Test. Lab Impact Testing software. The comparison results of modal parameters of four different vibration isolating systems show that the natural frequency of single-layer vibration isolating system is higher than that of non-isolation system and effectively avoids the second order resonance frequency. Furthermore the natural frequency of double-layer vibration isolating system has reduced due to the additional middle-mass. And the system's natural frequency decreases obviously with the increase of middle-mass which is far from resonance frequency and significantly improve the effect of vibration isolating system.

scholarly journals Fracture Healing Assessment Based on Impact Testing: In Vitro Simulation and Monitoring of the Healing Process of a Tibial Fracture with External Fixator

2017 ◽  
Vol 09 (07) ◽  
pp. 1750098 ◽  
Author(s):  
Francesca Di Puccio ◽  
Lorenza Mattei ◽  
Antonia Longo ◽  
Stefano Marchetti
Keyword(s):  
Fracture Healing ◽  
Modal Analysis ◽  
External Fixator ◽  
Healing Process ◽  
Experimental Modal Analysis ◽  
Impact Testing ◽  
Resonant Frequencies ◽  
Bone Callus ◽  
Healing Assessment

In clinical practice, bone healing is monitored with X-rays and manipulation. Its assessment is thus subjective, depending on the skills of the operator. Alternative and quantitative approaches have been proposed, generally based on the estimation of bone stiffness, which is known to increase with the healing process. The present study investigates the application of experimental modal analysis to fracture healing assessment focusing on fractures treated with an external fixator. The aim is to ascertain the capability of this approach to detect changes in the bone-callus stiffness as variations in the resonant frequencies despite the presence of the fixator, which might hide the bone response. In vitro tests were performed on a tibia phantom where the healing process was simulated creating three different types of callus surrogates, using glue and resin. The resonant frequencies of the phantom with screwed pins and of the phantom with the complete fixator were estimated. Results confirm an increase in the frequencies as the simulated bone-callus stiffness increases, encouraging the application of experimental modal analysis to fracture healing monitoring. This approach can offer remarkable advantages with respect to the actual standards: being non-invasive and quantitative, it would allow a more frequent healing monitoring.

scholarly journals Feasibility study of performing experimental modal analysis with oblique impact testing using various oblique impact directions

2020 ◽  
Vol 59 (1) ◽  
pp. 457-473
Author(s):  
Shin Yee Khoo ◽  
Yee Cheng Lian ◽  
Zhi Chao Ong ◽  
Zubaidah Ismail ◽  
Siamak Noroozi
Keyword(s):  
Modal Analysis ◽  
Feasibility Study ◽  
Oblique Impact ◽  
Experimental Modal Analysis ◽  
Impact Testing

Effect of Bass Bar Tension on Modal Parameters of a Violin's Top Plate

2015 ◽  
Vol 39 (1) ◽  
pp. 145-149 ◽  
Author(s):  
Ewa B. Skrodzka ◽  
Bogumił B.J. Linde ◽  
Antoni Krupa
Keyword(s):  
Modal Analysis ◽  
Experimental Modal Analysis ◽  
Mode Shapes ◽  
Modal Parameters ◽  
Normal Value ◽  
Modal Damping

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-).

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.

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