Nonlinear ultrasonic stimulated thermography for damage assessment in isotropic fatigued structures
| Autor: | Gian Piero Malfense Fierro, Michele Meo, Dmitri Ginzburg, Danielle Calla, Francesco Ciampa |
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| Rok vydání: | 2017 |
| Předmět: |
Materials science
Acoustics and Ultrasonics Acoustics Thermosonics 02 engineering and technology 01 natural sciences Laser vibrometer LDR 0103 physical sciences 010301 acoustics Nonlinear ultrasound business.industry Mechanical Engineering Structural engineering 021001 nanoscience & nanotechnology Condensed Matter Physics Rubbing Nonlinear system Thermography Mechanics of Materials Heat generation Harmonic Ultrasonic sensor Structural health monitoring 0210 nano-technology business Laser Doppler vibrometer |
| Zdroj: | Fierro, G P M, Calla, D, Ginzburg, D, Ciampa, F & Meo, M 2017, ' Nonlinear ultrasonic stimulated thermography for damage assessment in isotropic fatigued structures ', Journal of Sound and Vibration, vol. 404, pp. 102-115 . https://doi.org/10.1016/j.jsv.2017.05.041 |
| ISSN: | 0022-460X |
| Popis: | Traditional non-destructive evaluation (NDE) and structural health monitoring (SHM) systems are used to analyse that a structure is free of any harmful damage. However, these techniques still lack sensitivity to detect the presence of material micro-flaws in the form of fatigue damage and often require time-consuming procedures and expensive equipment. This research work presents a novel “nonlinear ultrasonic stimulated thermography” (NUST) method able to overcome some of the limitations of traditional linear ultrasonic/thermography NDE-SHM systems and to provide a reliable, rapid and cost effective estimation of fatigue damage in isotropic materials. Such a hybrid imaging approach combines the high sensitivity of nonlinear acoustic/ultrasonic techniques to detect micro-damage, with local defect frequency selection and infrared imaging. When exciting structures with an optimised frequency, nonlinear elastic waves are observed and higher frictional work at the fatigue damaged area is generated due to clapping and rubbing of the crack faces. This results in heat at cracked location that can be measured using an infrared camera. A Laser Vibrometer (LV) was used to evaluate the extent that individual frequency components contribute to the heating of the damage region by quantifying the out-of-plane velocity associated with the fundamental and second order harmonic responses. It was experimentally demonstrated the relationship between a nonlinear ultrasound parameter (βratio) of the material nonlinear response to the actual temperature rises near the crack. These results demonstrated that heat generation at damaged regions could be amplified by exciting at frequencies that provide nonlinear responses, thus improving the imaging of material damage and the reliability of NUST in a quick and reproducible manner. |
| Databáze: | OpenAIRE |
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