Spatial mapping of modal damping in vibrating plates.

2009 ◽  
Vol 126 (4) ◽  
pp. 2244 ◽  
Author(s):  
Hande Öztürk ◽  
J. Gregory McDaniel
Keyword(s):  
Spatial Mapping ◽  
Modal Damping ◽  
Vibrating Plates

Role of landmark for spatial mapping in non-rigid environments

2003 ◽  
Author(s):  
C. G. L. Cao ◽  
S. L. Waxberg ◽  
E. Smith
Keyword(s):  
Spatial Mapping

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-).

SPATIAL MAPPING OF URANIUM IN GROUNDWATER AND RISK ASSESSMENT AROUND AN ATOMIC POWER STATION IN INDIA

2016 ◽  
Vol 15 (4) ◽  
pp. 783-790 ◽  
Author(s):  
Vinod Kumar Garg ◽  
Manbir Singh ◽  
Yogendra Prakash Gautam ◽  
Avinash Kumar
Keyword(s):  
Risk Assessment ◽  
Atomic Power Station ◽  
Spatial Mapping ◽  
Power Station

Spatial mapping and attribution of Wyoming wind turbines

Data Series ◽  
10.3133/ds524 ◽  
2010 ◽  
Author(s):  
Michael S. O'Donnell ◽  
Tammy S. Fancher
Keyword(s):  
Wind Turbines ◽  
Spatial Mapping

scholarly journals Levantinizing the Balkans: Outlines for a Literary Geography of Encounters

2020 ◽  
Vol 55 (1) ◽  
pp. 64-82
Author(s):  
Guido Snel
Keyword(s):  
Eastern Mediterranean ◽  
Spatial Mapping ◽  
The Balkans ◽  
Literary Geography ◽  
The Caribbean ◽  
Etel Adnan

AbstractThe debate on the ‘where’ of the Balkans seem to be stuck between national paradigms and a nostalgia for cosmopolitanism. This essay explores an alternative spatial mapping of the region, opening it up to the wider Eastern-Mediterranean, in particular the fuzzy and contested notion of the Levant. First, it looks into various instances of ‘the Levant’ and ‘the Levantine,’ ranging from Turkish and Greek to Bosnian/Croatian/Serbian examples – with a particular focus on the latter. Secondly, by then ‘levantinizing’ the Balkans, in an explicit analogy to Édouard Glissant’s understanding of ‘creolization’ in the Caribbean, it attempts to draw the outlines of a geography of encounters. Finally, it offers a sample of what such a geography might look like and what its literary-historical repercussions might be, bringing together the work of Semezdin Mehmedinović and Etel Adnan.

A validated robust and automatic procedure for vibration analysis of bridge structures using MEMS accelerometers

2020 ◽  
Vol 14 (3) ◽  
pp. 327-354
Author(s):  
Mohammad Omidalizarandi ◽  
Ralf Herrmann ◽  
Boris Kargoll ◽  
Steffen Marx ◽  
Jens-André Paffenholz ◽  
...  
Keyword(s):  
Vibration Analysis ◽  
Damping Ratio ◽  
Fem Analysis ◽  
Cost Effective ◽  
Analysis Procedure ◽  
Modal Parameters ◽  
Bridge Structure ◽  
Modal Damping ◽  
Mems Accelerometers ◽  
Better Than

AbstractToday, short- and long-term structural health monitoring (SHM) of bridge infrastructures and their safe, reliable and cost-effective maintenance has received considerable attention. From a surveying or civil engineer’s point of view, vibration-based SHM can be conducted by inspecting the changes in the global dynamic behaviour of a structure, such as natural frequencies (i. e. eigenfrequencies), mode shapes (i. e. eigenforms) and modal damping, which are known as modal parameters. This research work aims to propose a robust and automatic vibration analysis procedure that is so-called robust time domain modal parameter identification (RT-MPI) technique. It is novel in the sense of automatic and reliable identification of initial eigenfrequencies even closely spaced ones as well as robustly and accurately estimating the modal parameters of a bridge structure using low numbers of cost-effective micro-electro-mechanical systems (MEMS) accelerometers. To estimate amplitude, frequency, phase shift and damping ratio coefficients, an observation model consisting of: (1) a damped harmonic oscillation model, (2) an autoregressive model of coloured measurement noise and (3) a stochastic model in the form of the heavy-tailed family of scaled t-distributions is employed and jointly adjusted by means of a generalised expectation maximisation algorithm. Multiple MEMS as part of a geo-sensor network were mounted at different positions of a bridge structure which is precalculated by means of a finite element model (FEM) analysis. At the end, the estimated eigenfrequencies and eigenforms are compared and validated by the estimated parameters obtained from acceleration measurements of high-end accelerometers of type PCB ICP quartz, velocity measurements from a geophone and the FEM analysis. Additionally, the estimated eigenfrequencies and modal damping are compared with a well-known covariance driven stochastic subspace identification approach, which reveals the superiority of our proposed approach. We performed an experiment in two case studies with simulated data and real applications of a footbridge structure and a synthetic bridge. The results show that MEMS accelerometers are suitable for detecting all occurring eigenfrequencies depending on a sampling frequency specified. Moreover, the vibration analysis procedure demonstrates that amplitudes can be estimated in submillimetre range accuracy, frequencies with an accuracy better than 0.1 Hz and damping ratio coefficients with an accuracy better than 0.1 and 0.2 % for modal and system damping, respectively.

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