doi:10.3850/978-981-08-7920-4_S2-S122-cd

ABSTRACT

In the field of non-destructive testing of structural components, active thermography methods are increasingly in demand. The most experience is available in testing of Carbon fiber reinforced plastic (CFRP) or similar types of composite materials. One of the emerging techniques is ultrasound excited thermography which has not been fully transferred to massive steel members used in constructional steelwork so far. This contribution demonstrates the use of high-frequency mechanical excitation to detect cracks in a hot-rolled steel girder and reduced plate specimens. Localized heating of the crack regions as well as distributed heating patterns due to material damping are observed. The influence of the tuned frequency and the pre-stressing is discussed. Achieved temperature increases of more than 10 Kelvin manifest the high potential of the test method. Besides the experimental results a 3D finite element simulation of the thermo-structural problem is conducted. The achieved numerical results are in a good agreement with experimental data of a performed ultrasonic sweep thermography.

Keywords: Steelwork, Fatigue, Cracks, Detection, Thermography, Ultrasound, Excitation.

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