000022003 001__ 22003
000022003 005__ 20170622131317.0
000022003 04107 $$aeng
000022003 046__ $$k2017-06-15
000022003 100__ $$aRoeck, Guido De
000022003 24500 $$aPROGRESS IN VIBRATION-BASED STRUCTURAL HEALTH MONITORING

000022003 24630 $$n6.$$pComputational Methods in Structural Dynamics and Earhquake Engineering
000022003 260__ $$bNational Technical University of Athens, 2017
000022003 506__ $$arestricted
000022003 520__ $$2eng$$aVibration based Structural Health Monitoring was and is still a hot topic in research. Much progress has been made both from the theoretical as well as the practical side. Vibration-based SHM traditionally makes use of uniaxial/triaxial accelerometers or velocity meters. Also sometimes inclinometers are installed. Recent trends in SHM are the use of high-rate GPS receivers, wave propagation-based piezoelectric ceramic sensing technology and optical fiber sensors for dynamic strain and temperature measurements. A particular challenge for structural health assessment is the discovery of small local damage. It is well known that for small damages, the changes in natural frequencies remain very low. Moreover, they are considerably influenced by environmental conditions (mainly temperature), which influence has to be eliminated on beforehand. Also modal displacements are rather insensitive to small stiffness perturbations. On the contrary, modal strains (or curvatures) are very receptive to small stiffness changes. Additionally, they immediately spot the damage location. Some authors have tried to derive curvatures from modal displacements but this procedure is very prone to even slight measurement and/or identification errors. Therefore, the key issue is the direct measurement of (modal) strains. However, the development of a distributed strain sensor network able to cope with the very low strain intensities during ambient excitation is still a challenge. In this paper by recent experiments on steel and concrete beams the extreme accuracy of dynamic measurements with optical FBG strain sensors is demonstrated. Another possibility to obtain precise modal strains would be the development of a transducer that amplifies the strains. In a recent research project, by using Topology Optimization, a transducer was developed that measures differential axial displacements over a sufficient long distance and at the same time is upscaling the strains. Results obtained with this transducer are reported. In this context, a new challenge for Optimal Sensor Placement is to deal with different sensor types, e.g. displacement transducers, accelerometers and strain sensors. For localization and quantification of damage, the most powerful method is FE-model updating based on minimizing differences between measured and calculated modal parameters. The addition of modal strains to the objective function of the minimization problem will improve the damage identification process.

000022003 540__ $$aText je chráněný podle autorského zákona č. 121/2000 Sb.
000022003 653__ $$aModal Analysis, Modal strains, Damage Assessment, Structural Health Monitoring, Bridges.

000022003 7112_ $$aCOMPDYN 2017 - 6th International Thematic Conference$$cRhodes Island (GR)$$d2017-06-15 / 2017-06-17$$gCOMPDYN2017
000022003 720__ $$aRoeck, Guido De
000022003 8560_ $$ffischerc@itam.cas.cz
000022003 8564_ $$s614750$$uhttp://invenio.itam.cas.cz/record/22003/files/18745.pdf$$yOriginal version of the author's contribution as presented on CD, section: [Semi plenary] Semi plenary
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000022003 962__ $$r21500
000022003 980__ $$aPAPER