Identification of Air Inhomogenities Inside of Tendon Ducts in Concrete via Boundary Integral Equations in Acoustics
Final Report Abstract
In the first half of the project, the first 3 tasks 1. Location and shape reconstruction of an object buried in an arbitrarily shaped cylinder for a given conductivity function; 2. Location and shape reconstruction of an object buried in a circular cylinder for a given conductivity function when separate steel wires are placed in the cylinder; 3. Extension of the problem (2) to the case when additionally the inhomogeneous conductivity function is unknown are successfully accomplished as it was proposed in the project application. The nature of the investigated NDT problem fits well to the nature of investigation with acoustic waves such that one can obtain information about core of a concrete structure covered by a metallic skin. Furthermore, for realistic parameters acceptable results were provided in the solution of inverse problem. This study shows that location and shape of an air gap or a big metallic structure in a concrete column can be obtained by four acoustic wave illumination at 10kHz in a few minutes with a standard PC. Note that this result is valid in a resonance region. Until now, reconstruction of a single object was considered and it was assumed that objects do not touch each other or to the boundary of the duct. The scope of the following studies could be extended to the algorithms for the multi air gap reconstructions, air gap and metalic structure reconstructions and to efficient location reconstruction algorithms for finding small voids.
Publications
- “Location and Shape Reconstructions of Objects Buried in Inhomogeneously Penetrable Cylinders”, IEEE- Electromagnetics in Advanced Applications (ICEAA), 2013 International Conference, Pg. 1505-1508, 2013
F. Yaman and Th. Weiland
- “A Boundary Integral Equation Approach for Nondestructive Testing of Tendon Ducts”, 7th International Conference Inverse Problems: Modeling and Simulation, Pg. 65, 2014
F.Yaman and Th. Weiland
- “Inhomogeneity Reconstructions in Tendon Ducts via Boundary Integral Equations”, NDT & E International, Volume 68, December 2014, Pages 66-72
F. Yaman and Th. Weiland
(See online at https://doi.org/10.1016/j.ndteint.2014.08.007)
