Issue 46

A. Kostina et alii, Frattura ed Integrità Strutturale, 46 (2018) 332-342; DOI: 10.3221/IGF-ESIS.46.30 340 (a) (b) Figure 8 : Distribution of the temperature rise as a result of the ultrasonic excitation by the force parallel to the crack plane calculated by the damping model: (a) t=0.1 s, (b) t=1 s. (a) (b) Figure 9 : Distribution of the temperature rise as a result of the ultrasonic excitation by the force parallel to the crack plane calculated by the Maxwell’s model: (a) t=0.1 s, (b) t=1 s. C ONCLUSION n this study, a numerical simulation of a crack detection by an ultrasonic thermography method is presented. The essence of the method is to affect the specimen by a periodic mechanical force with simultaneous recording of the temperature signal. The obtained temperature signal is generated mainly in the area containing cracks and other defects while the surrounding material keeps the same temperature. Local heating in the specimen is related to the dissipative processes arising during the mechanical vibration. In this work, two kinds of models describing energy dissipation and heat generation at the crack tip are considered: material (hysteretic) damping model characterized by an I