ARI guest talk by Prof. univ. dr. ing. Gilbert-Rainer GILLICH
08. Februar 2011
Institut für Schallforschung, Seminarraum
1040 Wien, Wohllebengasse 12-14, 1. Stock
We present a new method based on shift in natural frequencies to detect damages in beams and assess their location and severity. Typically, changes in natural frequency of beams are relatively small, even for an important reduction of their cross-section; this is one of the major difficulties in locating damages in this way. This research takes into account the particular manner in which the natural frequencies of the first ten modes change due to the occurrence of damage. The proposed method is a pattern recognition problem, the measured frequency changes being compared with values contained in a database, determined on models using the finite element method. A large number of damage locations and geometries were considered to complete this database. To verify the performance of the method, it was experimented on steel cantilever beams, each containing a single damage with arbitrary depth and location. By comparing the changes in frequency obtained through measurements with those determined on models, for the first ten vibration modes, it was possible to locate damages and estimate their geometry with high accuracy, which leads to the conclusion that the method can be successfully used.