An exact modal analysis approach to vibration analysis of structures with mass-spring subsystems and rotational joints

2019 ◽  
Vol 438 ◽  
pp. 191-219 ◽  
Author(s):  
Giuseppe Failla
Keyword(s):  
Modal Analysis ◽  
Vibration Analysis ◽  
Analysis Approach ◽  
Mass Spring

scholarly journals A New Vibration Analysis Approach for Monitoring the Working Condition of a High-Voltage Shunt Reactor

IEEE Access ◽  
2021 ◽  
Vol 9 ◽  
pp. 46487-46504
Author(s):  
Pengfei Hou ◽  
Hongzhong Ma ◽  
Ping Ju ◽  
Xuan Chen ◽  
Chao Zhu
Keyword(s):  
High Voltage ◽  
Vibration Analysis ◽  
Working Condition ◽  
Analysis Approach ◽  
Shunt Reactor

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.

scholarly journals Reduced Mass-Weighted Proper Decomposition for Modal Analysis

2011 ◽  
Vol 133 (2) ◽  
Author(s):  
Venkata K. Yadalam ◽  
B. F. Feeny
Keyword(s):  
Modal Analysis ◽  
Mass Distribution ◽  
Mass Matrix ◽  
Linear Interpolation ◽  
Modal Identification ◽  
Distributed Parameter ◽  
Arbitrary Mass ◽  
Spring System ◽  
Mass Spring ◽  
Proper Orthogonal

A method of modal analysis by a mass-weighted proper orthogonal decomposition for multi-degree-of-freedom and distributed-parameter systems of arbitrary mass distribution is outlined. The method involves reduced-order modeling of the system mass distribution so that the discretized mass matrix dimension matches the number of sensed quantities, and hence the dimension of the response ensemble and correlation matrix. In this case, the linear interpolation of unsensed displacements is used to reduce the size of the mass matrix. The idea is applied to the modal identification of a mass-spring system and an exponential rod.

Schwingungsanalyse an Industrierobotern*/Vibration analysis of industrial robots

2019 ◽  
Vol 109 (09) ◽  
pp. 656-661
Author(s):  
A. Karim ◽  
C. Michalkowski ◽  
A. Lechler ◽  
A. Verl
Keyword(s):  
Modal Analysis ◽  
Active Control ◽  
Normal Mode ◽  
Vibration Analysis ◽  
Industrial Robots ◽  
Vibration Exciter ◽  
Dynamic Vibration ◽  
Vibration Behavior ◽  
Working Space ◽  
Electromagnetic Vibration

Dieser Beitrag untersucht experimentell das dynamische Schwingverhalten eines „KR-500–3 MT“ von Kuka mittels eines elektromagnetischen Schwingerregers (Shaker) an insgesamt 28 Messposen im Arbeitsraum. Diese Untersuchungsmethode ist neuartig, da die Ergebnisse mit einer Modalanalyse mit Impulshammeranregung verglichen werden. Ab der vierten Eigenmode entstehen Unterschiede aufgrund der Anregungsform. Zudem wird an jeder Pose eine Messung mit angezogener Motorbremse und eine mit aktiver Regelung durchgeführt und miteinander verglichen.   This paper explores experimentally the dynamic vibration behavior of a Kuka KR-500 MT, using an electromagnetic vibration exciter (shaker) on a total of 28 measuring poses in the working space. As such studies are not known, the results are compared to a modal analysis with impulse hammer excitation. Starting from the fourth normal mode, differences arise due to the form of excitation. Both measurements are performed and compared with each other on each pose with brakes applied as well as with active control.

scholarly journals Suppression of Vibration Using Passive Receptance Method with Constrained Minimization

2008 ◽  
Vol 15 (6) ◽  
pp. 639-654 ◽  
Author(s):  
Murat Tursun ◽  
Eşref Eşkinat
Keyword(s):  
Vibration Analysis ◽  
Dynamic Stiffness ◽  
Aerospace Engineering ◽  
Graph Representation ◽  
Structural Vibration ◽  
Optimal Parameters ◽  
Combined System ◽  
Receptance Method ◽  
Mass Spring

Structural vibration analysis is used to suppress unwanted vibrations in many areas such as aerospace engineering, manufacturing, defense, automotive, etc. As a result of suppressing the unwanted vibration, the quality of the product is improved. Focusing on the minimization of the vibration amplitudes via a concept of receptance, a new and efficient method for calculating the receptance of a translational mass-spring-damper system with N masses and M absorbers (where N and M are any positive integer) is developed. The receptance of the combined system, in terms of the parameters of the main and absorber systems is derived, separately. The optimal parameters of the absorbers are then found. A methodology is derived using dynamic stiffness and linear graph representation in order to verify the dynamic stiffness, i.e., the inverse of the receptance, of the system.

Vibration Analysis for NDE of Ceramic Components

2021 ◽  
Author(s):  
Bernd Köhler ◽  
Kilian Tschöke ◽  
Mareike Stephan ◽  
Sergey Gartsev ◽  
Martin Barth
Keyword(s):  
Modal Analysis ◽  
Simultaneous Measurement ◽  
Vibration Analysis ◽  
Microphone Array ◽  
Acoustic Measurements ◽  
Laser Doppler Vibrometry ◽  
Mode Identification ◽  
Vibration Excitation ◽  
Ceramic Components ◽  
Signal Evaluation

Abstract In this contribution we study vibration testing for ceramic parts on the example of an electrolyte cup, used in a prospective power cells design. An adapted experimental arrangement for the vibration excitation and the acoustic measurements was built and tested. In parallel, extensive numerical modal analysis simulations were performed using ANSYS. The resonance spectra obtained by modelling agree with the experimentally determined spectra in such a way that the experimentally determined eigenfrequencies can be assigned to the cup modes. The correctness of this identification was verified by direct mode visualization with scanning laser doppler vibrometry. A much faster and potentially in-line capable method for experimental mode identification is the simultaneous measurement at several points using a microphone array and subsequent signal evaluation with operational modal analysis. This procedure was successfully tested. Features in the spectra connected with the presence of flaws are discussed. These features include the drop of some eigenfrequencies and the splitting of degenerated modes.

The Vibration Analysis of a Novel Vortex Flowmeter Based on Fiber Bragg Grating

2012 ◽  
Vol 485 ◽  
pp. 526-531 ◽  
Author(s):  
Hui Juan Dong ◽  
Yong Cai ◽  
Jun He ◽  
Ren Bing Liu
Keyword(s):  
Fiber Bragg Grating ◽  
Vibration Analysis ◽  
Axial Strain ◽  
Damping Ratio ◽  
Bragg Grating ◽  
Measuring Range ◽  
Fbg Sensor ◽  
Vortex Flowmeter ◽  
Acrylic Glass ◽  
Mass Spring

A novel fiber Bragg grating vortex flowmeter was designed in this work, where the Bragg grating was enfolded in a cylinder eddy generator. Bragg grating subject to force and the corresponding strain were analyzed. Subsequently, the relationships between grating’s axial strain and flow were developed. In order to improve the flowmeter's resolution, the system was simplified by a mass-spring-damper model, which was used to analyze resonance and choose acrylic glass as cylinder's material. In terms of the resolution of FBG sensor demodulation device and factors of vortex's formation, the measuring range of flowmeter is 1200L/h~5000L/h. The resolution is less than 40L/h with flow exceeding 2000L/h. The damping ratio is not sensitive to the flow when it is less than 2000L/h.

Minimizing the Effect of Out of Bandwidth Modes in Truncated Structure Models

1998 ◽  
Vol 122 (1) ◽  
pp. 237-239 ◽  
Author(s):  
S. O. Reza Moheimani
Keyword(s):  
Modal Analysis ◽  
Low Frequency ◽  
Control Design ◽  
Higher Order ◽  
Analysis Approach ◽  
Order Model ◽  
Infinite Dimensional ◽  
Higher Order Modes ◽  
Frequency Term ◽  
Zero Frequency

The modal analysis approach to modeling of structures and acoustic systems results in infinite-dimensional models. For control design purposes, these models are simplified by removing higher frequency modes which lie out of the bandwidth of interest. Truncation can considerably perturb the in-bandwidth zeros of the truncated model. This paper suggests a method of minimizing the effect of the removed higher order modes on the low frequency dynamics of the truncated model by adding a zero frequency term to the low order model of the system. [S0022-0434(00)01501-X]

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