Bias in modal parameters due to aliasing in the time domain

Agneni, A.

doi:10.1007/bf00430939

Cited by 1 publication

(1 citation statement)

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“…Modal frequencies ω i and damping ratios ζ i can be estimated from the obtained modal coordinates q i (t) (i = 1, …, r) by Fourier transform and logarithm decrement techniques, respectively, or using Hilbert transform (HT)-based SDOF analysis methods. [42] With the modal frequencies ω i , damping ratios ζ i , and full-field mode shapes φ i (x) (i = 1, …, r) estimated from the line of sight video measurements, the full-field modal model is established in the video domain where the full-field mode shapes (as many spatial points as the pixel number on the structure in the video frame) are in the pixel coordinate.…”

Section: Blind Mode Separation Of Principal Componentsmentioning

confidence: 99%

Spatiotemporal video-domain high-fidelity simulation and realistic visualization of full-field dynamic responses of structures by a combination of high-spatial-resolution modal model and video motion manipulations

Yang

Dorn

Mancini

et al. 2018

Struct Control Health Monit

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SummaryStructures with complex geometries, material properties, and boundary conditions exhibit spatially local dynamic behaviors. A high-spatial-resolution model of the structure is thus required for high-fidelity analysis, assessment, and prediction of the dynamic phenomena of the structure. The traditional approach is to build a highly refined finite element computer model for simulating and analyzing the structural dynamic phenomena based on detailed knowledge and explicit modeling of the structural physics such as geometries, materials properties, and boundary conditions. These physics information of the structure may not be available or accurately modeled in many cases, however. In addition, the simulation on the high-spatial-resolution structural model, with a massive number of degrees of freedom and system parameters, is computationally demanding. This study, on a proof-of-principle basis, proposes a novel alternative approach for spatiotemporal video-domain high-fidelity simulation and realistic visualization of full-field structural dynamics by an innovative combination of the fundamentals of structural dynamic modeling and the advanced video motion manipulation techniques.Specifically, a low-modal-dimensional yet high-spatial (pixel)-resolution (as many spatial points as the pixel number on the structure in the video frame) modal model is established in the spatiotemporal video domain with full-field modal parameters first estimated from line-of-sight video measurements of the operating structure. Then in order to simulate new dynamic response of the structure subject to a new force, the force is projected onto each modal domain, and the modal response is computed by solving each individual single-degree-of-freedom system in the modal domain. The simulated modal responses are then synthesized by the full-field mode shapes using modal superposition to obtain the simulated full-field structural dynamic response. Finally, the simulated structural dynamic response is embedded into the original video, replacing the original motion of the video, thus generating a new photo-realistic, physically accurate video that enables a --

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Section: Blind Mode Separation Of Principal Componentsmentioning

confidence: 99%