Bayesian oma of offshore rock lighthouses

Bayesian oma of offshore rock lighthouses: Surprises with close modes, symmetry and alignment

Brownjohn, James (University of Exeter)
Raby, Alison (Plymouth University)
Au, Siu Kui (University of Liverpool)
Zhu, Zuo (University of Liverpool)
Wang, Xinrui (University of Liverpool)
Antonini, A. (TU Delft Coastal Engineering)

Amador, Sandro D. R. (editor)
Brincker, Rune (editor)
Katsanos, Evangelos I. (editor)
Lopez Aenlle, Manuel (editor)
Fernandez, Pelayo (editor)

2019

A set of seven rock lighthouses around the British Isles was studied by a combination of forced and ambient vibration tests executed with some extreme logistical constraints. Forced vibration testing of the circular section masonry towers combined with experimental modal analysis identified modes with alignment assumed the same as the shaker as well as some interesting effects of helideck retrofit, whereas operational modal analysis revealed the considerable degree of uncertainty in mode shape alignment. Hence Bayesian operational modal analysis was used to characterise the uncertainty and find the best representation of mode shape direction. While perfectly axisymmetric towers would show a single frequency omnidirectional mode, OMA reveals the split modes and allows un unbiased view of directionality. The variability and uncertainty of these mode shape directions are further revealed using Bayesian OMA.

Assessment
Bayesian
Condition
Identification
Lighthouse
OMA
System

http://resolver.tudelft.nl/uuid:82d5b65e-f7a6-4f3e-8a2e-2d806b4af7f2

International Operational Modal Analysis Conference (IOMAC)

9788409049004

8th IOMAC - International Operational Modal Analysis Conference, Proceedings: 13-15 May, Copenhagen, Denmark

8th International Operational Modal Analysis Conference, IOMAC 2019, 2019-05-13 → 2019-05-15, Copengahen, Denmark

Accepted Author Manuscript

Institutional Repository

conference paper

© 2019 James Brownjohn, Alison Raby, Siu Kui Au, Zuo Zhu, Xinrui Wang, A. Antonini