Dynamic analysis of Sitar: A comparative study of operational and experimental modal analysis

2022 ◽  
pp. 107754632110421
Author(s):  
Beena Limkar ◽  
Gautam Chandekar
Keyword(s):  
Dynamic Analysis ◽  
Modal Analysis ◽  
Complex Geometry ◽  
Real Life ◽  
Experimental Modal Analysis ◽  
Musical Note ◽  
Stochastic Subspace Identification ◽  
String Instrument ◽  
Extreme Care ◽  
Subspace Identification Method

Dynamic analysis of Sitar, an Indian string instrument, is important for better understanding of the instrument behavior during performance. Sitar has complex geometry, and most of its components have anisotropic material properties, which generate a lot of challenges in performing numerical modal analysis. Considering this, an experimental approach of operational modal analysis (OMA) is performed on Sitar to extract its natural frequencies using the Stochastic Subspace Identification method. Hammer or shaker excitation required for conventional experimental modal analysis (EMA) has huge limitations of using harder hammer tips and high magnitude force as the instrument is delicate. However, to validate OMA results, EMA is performed with extreme care using an instrumented hammer with soft tip and with a very low excitation force. PolyMAX algorithm is used in EMA. It is observed that most of the correlated OMA and EMA modes lie in the audible frequency range. The maximum absolute percent error observed for these frequencies is 2.14%. All the modes obtained in OMA are significant as the string excitation simulate close to the real-life performing situation. Most of these modes map to musical note frequencies. Considering the detrimental effect of excitation required for EMA, OMA is a recommended method for extracting modal characteristics of Sitar.

Experimental Modal Analysis: Efficient Geometry Model Creation Using Optical Techniques

2006 ◽  
Vol 49 (2) ◽  
pp. 104-113 ◽  
Author(s):  
Steven Pauwels ◽  
Jan Debille ◽  
Jeff Komrower ◽  
Jenny Lau
Keyword(s):  
Modal Analysis ◽  
Numerical Models ◽  
Dynamic Properties ◽  
Real Life ◽  
Geometrical Model ◽  
Experimental Modal Analysis ◽  
Modal Parameter ◽  
Optical Techniques ◽  
Geometry Model ◽  
Modal Parameter Estimation

Experimental modal analysis (EMA) is widely used to characterize the dynamic properties of structures. Recently EMA is being used on more complex structures often involving hundreds of measurement points. Modal analysis results are frequently used in combination with numerical models, imposing higher standards on the quality of the modal parameter estimation and the accuracy of the geometry models. These requirements are often contradictory to the availability of test cells and prototypes. In order to solve this challenge, innovative solutions using optical techniques have been developed that simplify and accelerate the creation of a geometrical model of a test object, while at the same time increase the accuracy of measured coordinates. Industrial applicability of these techniques is proven by a number of benchmarks on real-life structures.

Experimental Modal Analysis of Motorized Spindle Based on Stochastic Subspace Identification

2011 ◽  
Vol 103 ◽  
pp. 469-474
Author(s):  
Jie Meng ◽  
Xiao An Chen
Keyword(s):  
Modal Analysis ◽  
Dynamic Characteristics ◽  
Time Domain ◽  
Experimental Modal Analysis ◽  
Modal Parameters ◽  
Vibration Velocity ◽  
Subspace Identification ◽  
Motorized Spindle ◽  
Stochastic Subspace Identification ◽  
The Time Domain

Experimental modal analysis is done to the grinding motorized spindle under 36000r/min. The corresponding theory and experimental plan are introduced. The time domain waveform is gained and the maximum vibration velocity is worked out. Stochastic Subspace Identification (SSI) is applied to study dynamic characteristics of motorized spindle which is running idle, then modal parameters are extracted. The correctness of the experimental method is validated, which has certain referential importance.

Modal Characterization of MEMS Switches via Output Only and Input/Output Identification Methods

2011 ◽  
Author(s):  
Joel M. Book ◽  
Samuel F. Asokanthan
Keyword(s):  
Modal Analysis ◽  
Noise Signal ◽  
Experimental Modal Analysis ◽  
Modal Parameters ◽  
Identification Algorithm ◽  
Base Excitation ◽  
Mems Devices ◽  
Stochastic Subspace Identification ◽  
Output Only

MEMS devices typically have moving or oscillating mechanical parts, and characterization of their dynamics, including their modal parameters, is highly desirable. This paper is concerned with experimental implementation of a Stochastic Subspace Identification (SSI) algorithm as well a base excitation based identification algorithm for experimental modal analysis of a micro-cantilever switch. A white noise signal applied to the built-in electrostatic actuator in the switches excited a response measured using microscanning Laser Doppler Vibrometry (LDV). In the case of identification via the SSI, only the output response was used while the base excitation based algorithm employed the input and the output signals. The modal parameters found using MACEC matched well with those predicted by theory, and the results obtained via the two experimental identification approaches are in good agreement, thus providing confidence in using the SSI approach for experimental modal analysis of MEMS structures.

Experimental Modal Characterization of MEMS Switches

2011 ◽  
Vol 403-408 ◽  
pp. 4598-4605
Author(s):  
Joel M. Book ◽  
Samuel F. Asokanthan ◽  
Tian Fu Wang
Keyword(s):  
Modal Analysis ◽  
Mechanical Systems ◽  
Noise Signal ◽  
Experimental Modal Analysis ◽  
Modal Parameters ◽  
Mems Devices ◽  
Micro Electro Mechanical Systems ◽  
Mems Switches ◽  
Stochastic Subspace Identification

MEMS devices, Micro Electro-Mechanical Systems, are electrical and mechanical systems with characteristic dimensions on the order of microns. Since these systems have moving mechanical parts, characterization of their dynamics, including their modal parameters, is highly desirable. This paper describes the validation of an existing implementation of the Stochastic Subspace Identification (SSI) algorithm, called MACEC, for experimental modal analysis of a micro-cantilever switch. A white noise signal applied to the built-in electrostatic actuator in the switches excited a response measured using microscanning Laser Doppler Vibrometry (LDV). The modal parameters found using MACEC matched well those predicted by theory, thus validating this combination for experimental modal analysis of MEMS structures.

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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