Operational Modal Analysis of a Rotating Cantilever Beam Using High-Speed Digital Image Correlation

Rizo-Patron, Sergio; Sirohi, Jayant

doi:10.2514/6.2016-1957

Cited by 7 publications

(4 citation statements)

References 19 publications

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“…The strongest vibration modes of WTB in flapwise and edgewise are identified from the power spectral density [13] or the cross-spectrum between various response pairs via the fast Fourier transform (FT) [7]. Ibrahim Time Domain method [32] was applied to the displacement time series of rotating helicopter rotor blades to identify the first three flexural ODS and resonant frequencies [17,33] or damping ratios [34]. A more DIC-specific data processing procedure was presented in [35], where ODS identification was carried out using only a single moving monochrome-lens high-speed camera without the need to synchronize between different camera views.…”

Section: Modal Analysismentioning

confidence: 99%

Review of digital image correlation application to large-scale composite structure testing

Janeliukštis

Xiao

2021

Composite Structures

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Section: Modal Analysismentioning

confidence: 99%

Review of digital image correlation application to large-scale composite structure testing

Janeliukštis

Xiao

2021

Composite Structures

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“…In recent years, image methods have been used to perform measurements in rotating objects, ranging from shafts [7] to propellers [6,8] and wind turbines [9]. Many of these works, such as [6,3,10,11,12,13,9,14,15,8,16,17], involve the acquisition of shape and displacements using 3D digital image correlation.…”

Section: Introductionmentioning

confidence: 99%

“…Other works involving rotating objects often do not approach this problem because the target of their research can be obtained even with misaligned axis. For example, Rizo-Patron and Sirohi were able to perform modal analysis [15,8], and obtain the natural frequencies and mode shapes, without considering misalignments, as it had no eect on these results.…”

Section: Introductionmentioning

confidence: 99%

Correction of rigid body motion in deformation measurement of rotating objects

2018

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When using image-based measurement solutions for monitoring the displacement of rotating objects, it is necessary to trigger the image acquisition system at precise positions. Triggering errors lead to articial rigid motions in the output that are hard to remove independently. Thus, a methodology was developed to enable the removal of these errors while maintaining the true rotations, such as those relating to the angle of attack. The proposed methodology involves detecting an object's axis and centre of rotation and then using that knowledge to correct acquired deformation data. Additionally, it also enables the representation of displacements in a more representative coordinate system, i.e., one that includes the rotation axis. While common solutions for this problem use either manually positioned references or track a single-point's rotation, the proposed methodology is based on a least-squares approach. This results in a more accurate measurement of the rotation axis and, thus, improves the quality of the results. The methodology was experimentally validated and it was shown that its implementation is accurate, with errors below 3 %. Additionally, it was applied to an actual experimental situation and the results were compared to the uncorrected data, while highlighting the most relevant improvements.

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“…The technique uses a pair of high speed cameras and image processing algorithms to track patterns and to find deformations of structures. The technique has been applied to monitor vibrations of wind turbine blades [24][25][26][27][28], helicopter rotors [29][30][31], and civil structures [32]. Using this technique to measure mode shapes of a guitar can provide valuable information and has not been explored by the scientific community.…”

Section: Introductionmentioning

confidence: 99%

Extracting vibration characteristics of a guitar using finite element, modal analysis, and digital image correlation techniques

Patil

Baqersad

Ludwigsen

et al. 2016

Journal of the Acoustical Society of America

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The sound quality generated by the guitar depends on the vibration characteristics (i.e. natural frequencies and mode shapes) of this instrument. Thus, it is of particular interest to the guitar manufacturers to be able to obtain global information about the characteristics of the guitar. Traditional sensors can only measure at discrete locations. However, digital image correlation (DIC) can measure full-field data on the surface of the structure. In the current paper, a finite element (FE) model of a guitar with free boundary configurations was developed using quadratic solid elements. An eigensolution was performed on the FE model to determine its natural frequencies and mode shapes. In order to validate the numerical results, a modal impact hammer test was performed on the instrument in a free configuration. Furthermore, a measurement was performed on the guitar using the DIC technique. In this measurement as well, the guitar was suspended in a free configuration, but was driven using a broadband acoustic excitation generated by a sound source. The response of the guitar to the excitation was recorded using a pair of high-speed cameras. The recorded images were processed to extract the natural frequencies and mode shape of the guitar.

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Operational Modal Analysis of a Rotating Cantilever Beam Using High-Speed Digital Image Correlation

Cited by 7 publications

References 19 publications

Review of digital image correlation application to large-scale composite structure testing

Review of digital image correlation application to large-scale composite structure testing

Correction of rigid body motion in deformation measurement of rotating objects

Extracting vibration characteristics of a guitar using finite element, modal analysis, and digital image correlation techniques

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