Simulation of Frictional Heat Generation at Crack Interfaces for Non-Destructive Defect Characterization

Speaker:
Truyaert, Kevin; KU Leuven Kulak; Belgium

Authors:
Aleshin, V.; Joint International Laboratory LICS/LEMAC, Institute of Electronics, Microelectronics and Nanotechnologies; France
Delrue, S.; Wave Propagation and Signal Processing Research Group; Belgium
Truyaert, K.; Wave Propagation and Signal Processing Research Group; Belgium
Van Den Abeele, K.E.A.; University of Leuven; Belgium

ID: ECNDT-0182-2018
Session: Thermography and Thermosonics 2
Room: H1
Date: 2018-06-14
Time: 11:30 - 11:50

Early non-destructive detection, localization and characterization of cracks in industrial settings has grown of importance in recent years, mainly because initially small defects in a material can develop into large cracks, eventually leading to failure. The main challenge in the field of Non-Destructive Evaluation (NDE) is to develop methods that allow fast detection and easy characterization of the defect. A promising NDE technique, capable of performing a full field inspection in a fast manner, is ultrasonic thermography. This technique is based on the measurement of local surface temperature variations caused by defects when exposed to ultrasonic excitation. To intensify the relatively inefficient frictional heat generation at the defect interface, the concept of Local Defect Resonance (LDR) can be used to efficiently transfer the excitation energy to the defect by exciting the object at a characteristic frequency of the defect. Detection and localisation of defects using this approach has already been illustrated experimentally. However, in order to be able to fully characterise a defect, the development of a well underpinned model that is capable of describing the efficient transport of energy towards the defect, and allows to represent the generated heat due to friction effects, is crucial. The goal of this study is therefore to study frictional heat generation at the interface of a crack with rough surfaces. Apart from total sliding effects, the introduction of roughness results in the appearance of an additional contact regime of partial slip. In our model, we include this behaviour using the previously developed Method of Memory Diagrams (MMD) to obtain a hysteretic solution of the tangential contact problem that can be directly linked to heat generation. In future work, the proposed model will be further exploited to develop (inverse) methods that can be used for defect characterization, e.g. by direct comparison with experiments.