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.

scholarly journals Transmissibilty-Based Operational Modal Analysis for Flight Flutter Testing Using Exogenous Inputs

2012 ◽  
Vol 19 (5) ◽  
pp. 1071-1083 ◽  
Author(s):  
Christof Devriendt ◽  
Tim De Troyer ◽  
Gert De Sitter ◽  
Patrick Guillaume
Keyword(s):  
Modal Analysis ◽  
Frequency Domain ◽  
Experimental Modal Analysis ◽  
Operational Modal Analysis ◽  
Modal Parameters ◽  
Input Output ◽  
Output Only ◽  
Flutter Testing

During the recent years several new tools have been introduced by the Vrije Universiteit Brussel in the field of Operational Modal Analysis (OMA) such as the transmissibility based approach and the the frequency-domain OMAX concept. One advantage of the transmissibility based approach is that the ambient forces may be coloured (non-white), if they are fully correlated. The main advantage of the OMAX concept is the fact that it combines the advantages of Operational and Experimental Modal Analysis: ambient (unknown) forces as well as artificial (known) forces are processed simultaneously resulting in improved modal parameters. In this paper, the transmissibility based output-only approach is combined with the input/output OMAX concept. This results in a new methodology in the field of operational modal analysis allowing the estimation of (scaled) modal parameters in the presence of arbitrary ambient (unknown) forces and artificial (known) forces.

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.

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-).

scholarly journals Output-Only Modal Analysis Based on Improved Empirical Mode Decomposition Method

2015 ◽  
Vol 2015 ◽  
pp. 1-12 ◽  
Author(s):  
Shiqiang Qin ◽  
Qiuping Wang ◽  
Juntao Kang
Keyword(s):  
Modal Analysis ◽  
Empirical Mode Decomposition ◽  
Modal Parameters ◽  
Band Pass Filter ◽  
Pass Filter ◽  
Random Decrement Technique ◽  
Mode Decomposition ◽  
Frequency Components ◽  
Output Only ◽  
Emd Method

The output-only modal analysis for bridge structures based on improved empirical mode decomposition (EMD) is investigated in this study. First, a bandwidth restricted EMD is proposed for decomposing nonstationary output measurements with close frequency components. The advantage of bandwidth restricted EMD to standard EMD is illustrated by a numerical simulation. Next, the modal parameters are extracted from intrinsic mode function obtained from the improved EMD by both random decrement technique and stochastic subspace identification. Finally, output-only modal analysis of a railway bridge is presented. The study demonstrates the mode mixing issues of standard EMD can be restrained by introducing bandwidth restricted signal. Further, with the improved EMD method, band-pass filter is no longer needed for separating the closely spaced frequency components. The modal parameters extracted based on the improved EMD method show good agreement with those extracted by conventional modal identification algorithms.

Experimental Modal Analysis of Car's Body-in-White

2011 ◽  
Vol 346 ◽  
pp. 627-633 ◽  
Author(s):  
He Li ◽  
Shi Bo Fu ◽  
Bang Chun Wen
Keyword(s):  
Modal Analysis ◽  
Single Point ◽  
Test System ◽  
Experimental Modal Analysis ◽  
Modal Parameters ◽  
Modal Characteristics ◽  
Car Body ◽  
Modal Test ◽  
Acceleration Sensors ◽  
Body In White

To reduce noise and make the structure of the car more rational, we established modal test system of car's body-in-white in this paper. Car body-in-white was mounted on rigid platform with four coil springs. The car was excited by an electromagnetic exciter. The method of single-point excitation and multi-point collecting vibration was used in this test. Excitation point was chosen in the bearing beam. Signals picked up by the acceleration sensors were processed in the software of Mescope. With this system, different modal frequencies and modal characteristics of the car are acquired. The results show that modal parameters are effective and reliable and those parameters can be basis for the designer to improve the structure of the car.

Experimental Modal Analysis of the Advanced Combat Helmet

2011 ◽  
Author(s):  
Alessio Medda ◽  
Jay Shridharani ◽  
Cameron D. Bass ◽  
Valeta Carol Chancey
Keyword(s):  
Modal Analysis ◽  
Experimental Modal Analysis ◽  
Measurement Noise ◽  
Local Models ◽  
Frequency Model ◽  
Analysis Techniques ◽  
Input And Output ◽  
Specific Input ◽  
Least Squares Techniques

In this work we present a study of the characterization of an Advanced Combat Helmet (ACH) using experimental modal analysis techniques. A medium-sized helmet was impacted at different location and the vibration response was used to estimate a global frequency model. This was achieved using the modal parameters of the local models obtained for a specific input-output location and combining them in a global model. The estimation of the frequency model was done using well-established least squares techniques, while the contribution of measurement noise in input and output was considered.

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