Kocur, Georg

ETH Zürich Georg Kocur Institut f. Baustatik und Konstruktion HIL E 34.2 Wolfgang-Pauli-Str. 15 8093 Zürich Telefon: +41 44 633 34 42 E-Mail:

Research

Analysis of Relations between Crack Growth and Acoustic Emissions in Structural Concrete
(Analyse der Zusammenhänge zwischen Risswachstum und Schallemissionen in Stahlbeton)

Acoustic emission (AE) stands for the release of strain energy due to a deformation process. The released energy becomes manifested in an excitation of elastic waves that propagate inside the structure. The emitted waves are recorded on the structure surface by piezoelectric sensors and converted into acoustic signals. The gained information is of practical interest for non-destructive testing.
In concrete structures AE indicates a destruction process in the respective structure. A convenient application in structural engineering is the detection of concrete cracking and reinforcement ruptures by analyzing AE events that occur during loading. Presently AE activity can be used to differentiate fracture types using moment tensor components. However, the emitted signals provide only reasonable information for cracks that nucleate in an intact medium that has not already been pervaded by other cracks. For further crack growth the effective propagation velocities decrease due to induced micro-cracking. Rudimental information is available for relating crack formation to AE. Additionally, only general statements can be made concerning health conditions. Due to disturbing effects, such as scattering, dispersion and reflection, it is hard to determine what exactly is being detected and the emitted signals certainly cannot be identified as crack growth. Up until now applications for the non-destructive testing using AE are limited. These facts provide the main motivation for a differentiated study concerning the relationship between crack growth and AE activity in reinforced concrete structures.

My recent publications

• Kocur, G. K., Vogel, T., Saenger, E. H. (2011).
  Crack localization in a double-punched concrete cuboid with time reverse modeling of acoustic emissions,
  International Journal of Fracture, Volume 171, Number 1, pp. 1-10.
• Kocur, G. K., Saenger, E. H., Vogel, T. (2011).
  Time Reverse Modeling versus Automatic Onset Detection: A Study on the Localization of Acoustic Emissions in Reinforced Concrete,
  Proceedings of NDTMS-2011 International Symposium on Nondestructive Testing of Materials and Structures, Istanbul, Turkey, May 15-18, 2011.
• Saenger, E. H., Kocur, G. K., Jud, R., Torrilhon, M. (2011).
  Application of time reverse modeling on ultrasonic non-destructive testing of concrete,
  Journal of Applied Mathematical Modelling, Volume 35, pp. 807–816.
• Kocur, G. K., Saenger, E. H., Vogel, T. (2010).
  Elastic wave propagation in a segmented X-ray computed tomography model of a concrete specimen,
  Journal of Construction and Building Materials, Volume 24, pp. 2393–2400.
• Kocur, G. K., Vogel, T. (2010).
  Classification of the damage condition of preloaded reinforced concrete slabs using parameter-based acoustic emission analysis,
  Journal of Construction and Building Materials, Volume 24, pp. 2332–2338.
• Kocur, G. K. (2008).
  Wave propagation properties of structural concrete with respect to acoustic emission analysis,
  Proceedings of 7th International PhD Symposium in Civil Engineering, Stuttgart, Germany, September 11-13, 2008.
• Kocur, G. K., Park, S.-H. (2007).
  Adaptive modeling of transient wave propagation in an unbounded elastic waveguide,
  Proceedings of 1st International Conference on Computational Dynamics and Earthquake Engineering, Rethymno, Crete, Greece, June, 2007.

Teaching activities

Other activities

• Member rilem TC NUM "Numerical modelling of cement-based materials"