Development of Efficient Dynamic Aeroelasticity Model for High Fidelity Pointing Accuracy Assessment of VLBI Earth-Based Radio Antennas

Nieto, Michelle Guzman; Thomas, Paul Vazhayil; Saad, M. S.; Brown, Gary L.; Hilliard, L.

doi:10.1007/s42405-019-00238-6

Cited by 6 publications

(31 citation statements)

References 31 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…[1], and {𝚽 𝑅𝑂𝑀−2 } 𝑠 is the s-th mode shape of the ROM implemented in this work. As it can be seen from Figure 7.4, the normal modes of the new reduced model implemented by the author present good correlation with the model developed by Nieto et al [1]. A small loss of correlation was observed between the mode shapes 17 and 18, which represent an inversion of the order of appearance of such mode shapes.…”

Section: Final Reduced Order Model Creationmentioning

confidence: 52%

“…When excited close to resonance frequencies, the dynamic loads can cause excessive vibrations in the structures, resulting in loss of accuracy [1,2], structural instabilities [3,4] material fatigue [5,6],…”

Section: List Of Figuresmentioning

confidence: 99%

“…In order to carry the optimization procedure with the FE model of the 12m VLBI antenna, it is necessary to numerically reduce the Detailed FE model (DFEM) provided by the industrial partner, which is depicted in Figure 7.2. The previous work from Nieto et al [1] subjected this antenna model to an order reduction procedure, being able to considerably minimize the computational cost of the simulation. However, the computation time was still relatively high when considering its implementation in the optimization framework, specially using MOGA as the optimizer method, since it requires several generations and a high population number to achieve the convergence of the results.…”

Section: Final Reduced Order Model Creationmentioning

confidence: 99%

“…The criteria utilized to further reduce the model generated by Nieto et al [1] is based in the elimination of grid points from the main ASET card that do not participate in the following components of the simulation:…”

Section: Final Reduced Order Model Creationmentioning

confidence: 99%

“…• Monitoring grid points that were defined in the work of Nieto et al [1] (those are specifically related to the reference and target nodes that are used to assess the pointing accuracy of the antenna).…”

Section: Final Reduced Order Model Creationmentioning

confidence: 99%

See 4 more Smart Citations

Dynamic Aeroelastic Response Attenuation of Aerospace Structures Employing Passive Tuned Mass Dampers

Gasparetto¹

View full text Add to dashboard Cite

This thesis proposes an optimization procedure to achieve the best configuration of Multiple Degrees of Freedom (MDOF) tuned mass dampers (TMD) to mitigate the global dynamic aeroelastic response of aerospace structures. The TMD design parameters are investigated in terms of their individual mass, stiffness, damping, and location on the target structure. In order to determine the optimum sets of TMD, a Multi-Objective design optimization employing Genetic Algorithm (MOGA) is implemented, where the selected fitness functions for the analysis are the minimization of the total mass included with the resonators and concurrent minimization of the peak displacement at a specific structural nodes in space.Two case studies are presented where the method proposed is tested to minimize the pointing error of large Earth-based radio antenna structures. Fourteen different operational scenarios of wind gust are considered employing two models of atmospheric disturbances, namely, the Power Spectral Density (PSD) represented by the Davenport spectrum (DS), and the Tuned Discrete Gust (TDG) where the dynamic aeroelastic response of the structure is analyzed in the frequency and the time domains, respectively.In the first case study, the inclusion of multiple-TMD in the antenna structure is analyzed and compared with different placement configurations of the multiple-TMD devices. Here, the performance of the antenna structure in the form of its pointing error and the corresponding multiple-TMD inclusion are discussed at length. It is found that the placement of the multiple-TMD in the primary reflector of the antenna provides a maximum reduction in the pointing error of the antenna of 62.0% and 39.2% while subject to PSD and TDG gust disturbances , respectively. iv In the second case study, a single-TMD configuration is investigated to concurrently attenuate the aeroelastic response of all 14 operational cases considering the frequency and time-domain gust models. It is found that the optimal solutions are capable of reducing the structural response by an average of 66% and 50% for the PSD and TDG gust excitation scenarios, respectively, with a mass inclusion of 1% of the total mass of the antenna structural.Finally, this study proposes an advanced framework to estimate the optimal parameters of TMD attenuation devices, under complex loadings conditions, as an initial step in the direction of the use of such passive systems in applications that commonly employ active or semi-active attenuation solutions.

show abstract

Section: Final Reduced Order Model Creationmentioning

confidence: 52%