Systematic planning and execution of ﬁnite element model updating
2015 (English)Licentiate thesis, monograph (Other academic)
In design of bridges and for estimation of dynamic properties and load carrying capacity Finite Element Method (FEM) is often used as a tool. The physical quantities used in the Finite Element (FE) model are often connected to varying degrees of uncertainty. To deal with these uncertainties conservative parameter estimates and safety factors are used. By calibrating the bridge FE model to better ﬁt with the response of the real structure, less conservative parameter values can be chosen. This method of comparing measured and response with estimates from a FE model and calibrating the model parameters is called Finite Element Model Updating (FEMU).
In the present thesis diﬀerent aspects of FEMU are investigated. The ﬁrst part comprises a literature review covering all aspects of FEMU with special focus on the choice of updating parameters, objective functions for iterative updating procedures and the automatic pairing of modes. This part is concluded with a ﬂowchart suggesting a systematic approach to a FEMU project.
In the second part of the text two bridge case studies are presented. In the ﬁrst case study a railway bridge in the north of Sweden is studied. A detailed FE bridge model from a previous project is used as a simulation model for extraction of modal data by eigenvalue analysis. Then simpliﬁed models are created and attempts to update these models are performed. The updating parameters are chosen based on a simple sensitivity analysis. Tests are performed to investigate the inﬂuence of chosen updating parameters and objective function on the computational cost and the quality of the updated model.
Case study number two is more comprehensive and focuses on the sensitivity analysis for the choice of updating parameters and on the choice of objective function. A road bridge in the Stockholm area is used and as for case study one a detailed model from a previous project is used as simulation model. Also a new criteria for the automatic pairing of modes is presented and tested. In the end an attempt to verify two of the updated models is performed.
Place, publisher, year, edition, pages
Stockholm: KTH Royal Institute of Technology, 2015. , x, 154 p.
TRITA-BKN. Bulletin, ISSN 1103-4270 ; 134
dynamics, ﬁnite element model updating, bridge, objective function, updating parameter, mode pairing
dynamik, ﬁnita element modelluppdatering, bro, målfunktion, uppdateringsparameter, matchning av moder
Research subject Civil and Architectural Engineering
IdentifiersURN: urn:nbn:se:kth:diva-172295OAI: oai:DiVA.org:kth-172295DiVA: diva2:846716
2015-09-03, Sal M108, Brinellivägen 23, KTH, Stockholm, 13:00 (English)
Plos, Mario, Docent
Pacoste, Costin, DocentKaroumi, Raid, Docent
FunderSwedish Research Council for Environment, Agricultural Sciences and Spatial Planning, 242-2010-1084
QC 201508252015-08-252015-08-152015-08-25Bibliographically approved