In the metallurgy industry, the detection of defects in products like ingots would permit to reject or not defective parts before their transformation with another manufacturing process, which could have an enormous time and financial impact.
This thesis presents the application of an quantitative imaging method, developped by Huthwaite& Simonetti (2011) and called Hybrid Algorithm for Robust Breast Ultrasound Tomography (or HARBUT), for the detection of heterogeneities inside a steel ingot. This could present a high interest to the metallurgical industry for the reliability of such structures.
A finite-element model was developped with Pogo FEA software (Huthwaite (2014)) in order to simulate a steel bar immersed in water. The conclusion of this simulation study is that HARBUT can be applied to produce an estimated sound of speed map in a slice of this ingot sample. The average reconstructed speed inside it was estimated with a relative error of 2 %. The modelled heterogeneities was well detected, with a spatial resolution of a half of a wavelength and with a relative error of around 10%. These results come from the modelling of a steel bar immersed in water with the transducers which are in contact with it.
Experimental validation was partially performed for the reconstruction of the speed of sound map of this sample extracted from a large steel ingot, forged and heat treated, which was studied in Dupont-Marillia et al. (2017). A difference of 10 m/s was observed in the velocity map in the center of this bar and with a relative error of 15% for the average speed inside it. However, phase identification and macrostructure cartography was not well performed, because of the Born approximation used in HARBUT for the diffraction tomography, which is off-limits in this high-contrast scenario.
| Date | 21 Jul 2021 |
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| Original language | French |
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| Awarding Institution | - École de technologie supérieure
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| Supervisor | Pierre Bélanger (Supervisor) |
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Lim, A. (Author),
Bélanger (Supervisor),
21 Jul 2021Student thesis: Master's thesis › Master in Engineering: Mechanical Engineering