Authors:
Aleksandrs Sisojevs
1
;
Alexey Tatarinov
2
;
Mihails Kovalovs
1
;
Olga Krutikova
1
and
Anastasija Chaplinska
2
Affiliations:
1
Riga Technical University, 1 Kalku Str. Riga, Latvia
;
2
Institute of Electronics and Computer Science, 14 Dzerbenes Str., Riga, Latvia
Keyword(s):
Pattern Recognition, DFT, Ultrasonic Testing, Bone, Concrete.
Abstract:
An adequate assessment of the condition of versatile structural materials of different origin, from hard biological tissues (cortical bone) to objects of engineering infrastructure facilities (concrete), may encounter difficulties due to their complex and multilayer structure. Traditional ultrasonic testing based on the measurement of single parameters do not allow separating the complex influences of acting factors. Thus, the diagnosis of osteoporosis is complicated by the adverse influence of the thickness of the layer of soft tissue covering bone, when assessing the porosity of the bone. In the evaluation of deterioration processes in concrete, it is important to discriminate the depth of the deteriorated surface layer of concrete and the degree of the material degradation in this layer. The evaluation approach implementing the methods of pattern recognition has been proposed. The initial data set comprised ultrasonic signals obtained at different frequencies in specimens with dif
ferent values of the parametrs according to a planned grid of the parameters of ineterest. The signals were obtained by surface profiling of the specimens by a pair of emitting and receiving transducers. In this study, an approach to evaluate parameters of interest using pattern recognition methods applied to ultrasonic signals processed by the Digital Fourier Transform was verified. The estimation model was based on the statistical analysis of the magnitude of the spectrum of the original ultrasonic signals. Decision rules were created based on the testing of a number of specimens forming the training set and calculation of the statistical criteria. Comparative testing of examination specimens demonstrated the adequacy of the proposed method as a potentially universal approach for evaluation of different kind of objects.
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