Automated estimation of the modal parameters for civil structures

PhD defense, Thursday 27 September 2018. Peter Olsen.

2018.09.27 | Olivia Elsebeth Belling-Nami

Peter Olsen

During his studies, Peter researched the possibility of automating the process of estimating the modal parameters using Operational Modal Analysis (OMA). In OMA the measured vibrations caused by random loads from waves, wind or traffic is used to extract the modal parameters, which describes the dynamical properties of a structure. Which possess great value in terms of describing and monitoring the condition of a structure. In the study, the classic identification techniques has been used as basis, in combination with band pass filtering, following the idea of estimating a few modes at the time. Repeating this throughout the frequency range, results in a population of estimates. In this population, the stable estimated modal parameters gather in groups. Hierarchical clustering has been applied in order to extract a final set of modal parameters. The approach has been tested on large experimental data sets from real structures.

The new research findings contribute to a new approach towards automated OMA, with a minimum of user interaction, when estimating the modal parameter of a structure, which is very useful in monitoring of structures.

The PhD degree was completed at the Department of Engineering (ENG), Science and Technology, Aarhus University.

This résumé was prepared by the PhD student.

Time: Thursday 27 September 2018 at 13:30
Place: 3210- 04.061, Navitas, Department of Engineering, Inge Lehmanns Gade 10, 8000 Aarhus C
Title of PhD thesis:
 Automated Operational Modal Analysis - Using Low Order Time Domain Identification Techniques and the Sliding Filter Stabilization Diagram.
Contact information: Peter Olsen, e-mail:, tel.:41 89 32 76
Members of the assessment committee:
Professor Guido De Roeck, Department of Civil Engineering, KU Leuven, Belgium
PhD Dimitri Tcherniak, Brüel & Kjær, Denmark
Associated Professor Steffen Petersen (chair), Department of Engineering, Aarhus University
Main supervisor:
Professor Poul Henning Kirkegaard, Department of Engineering, Aarhus University
Professor Rune Brincker, Department of Civil Engineering, Technical University of Denmark
Language: The PhD dissertation will be defended in English

The defence is public.
The PhD thesis is available for reading at the Graduate School of Science and Technology/GSST, Ny Munkegade 120, building 1520, rooms 128-134, 8000 Aarhus C.

PhD defence
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Olivia Elsebeth Belling-Nami

Revised 21.09.2018