doctoralThesis
Identificação de descontinuidades em peças metálicas utilizando sinais ultrassônicos e técnicas de problemas inversos
Fecha
2015-07-17Registro en:
GUARNERI, Giovanni Alfredo. Identificação de descontinuidades em peças metálicas utilizando sinais ultrassônicos e técnicas de problemas inversos. 2015. 157 f. Tese (Doutorado em Engenharia Elétrica e Informática Industrial) – Universidade Tecnológica Federal do Paraná, Curitiba, 2015.
Autor
Guarneri, Giovanni Alfredo
Resumen
The present work proposes an algorithm to identify internal discontinuities in metallic specimen from A-scan ultrasonic signals. Discontinuities are identified by their shape, size, orientation and location. This algorithm is based on inverse problems. The identification of discontinuities is modeled using a novel approach. The discontinuity is modeled by two distinct elements: its scattering amplitude and its center location. Through this approach, the identification problem is split into two sub problems. The first is a reconstruction problem to find the location of the discontinuity. The second is a model identification problem to estimate geometric parameters of the discontinuity. Simulations and experimental validation show that the localization problem is satisfactorily solved using the UTSR (ultrasonic sparse reconstruction) algorithm. The characterization of discontinuities is carried out by an algorithm based on non-linear least squares with l1 norm regularization. The results obtained with simulated data as well with experimental data show a fine estimation of discontinuities.