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摘要
Ultrasound-excited vibrothermography (VT) is a newly developed version of InfraRed (IR) thermographic Non-Destructive Testing (NDT), but the relation between the defect signal and mechanical parameters is fuzzy due to the complexity of thermo-mechanical coupling and the interaction effects of multiple factors, so the design of operation conditions of VT is highly-dependent on the experience of operators. In order to reveal the relations of the defect signal vs. the mechanical parameters, and to enable the optimisation of operation conditions, a mathematical model was presented to simulate the heat generation and heat transfer that occur during VT. The heat power produced in a crack and the temperature increase at the crack area were solved by an analytical approach. The function of the temperature increase at the crack area vs. the mechanical parameters including the damp, mass, stiffness, amplitude and frequency of the stimulation force, friction coefficient and normal force in crack faces, excitation duration, etc., was deduced. The dependencies of temperature signals on parameters of a material and ultrasonic stimulation were theoretically analysed. The crack signature on an aluminium sample was imaged by an IR camera and compared with the theoretical predictions. The effects of experimental factors including the support condition, excitation frequency, duration and power, etc., on the crack signature were partially compared. The results show that the theoretical predictions are in agreement with the observed responses, and the influences of various mechanical parameters on VT can be quantitatively described by the analytical model presented.
- 出版日期2015-7-3
- 单位北京航空航天大学
