Synthesizing Data of Active Infrared Thermography under Optical and Ultrasonic Stimulation of Products Made of Complex-S
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MAL METHODS
Synthesizing Data of Active Infrared Thermography under Optical and Ultrasonic Stimulation of Products Made of Complex-Shaped CFRP A. O. Chulkova, *, V. P. Vavilova, D. A. Nesteruka, A. M. Bedareva, Sh. Yarkimbaeva, and B. I. Shagdyrova a
Tomsk Polytechnic University, Tomsk, 634050 Russia *e-mail: [email protected]
Received May 27, 2020; revised June 9, 2020; accepted June 11, 2020
Abstract—We propose a combined method for thermal nondestructive testing using optical and ultrasonic stimulation by means of combining individual thermograms obtained at the corresponding time points. The resulting sequences of infrared thermograms provide more efficient identification of defects of various types and can also be processed using well-known algorithms, for example, thermographic signal reconstruction, principal component analysis, etc. We obtained experimental results on a composite CFRP sample imitating aircraft ribs using a robotic manipulator. Keywords: robotic thermal testing, composite, optical stimulation, ultrasonic stimulation, data synthesis DOI: 10.1134/S1061830920070037
INTRODUCTION It is advisable to conduct thermal testing (TT) for various types of defects in composite materials using sources of thermal stimulation of various physical nature. For example, optical heating with halogen and xenon lamps is used to detect delaminations and for thickness gauging [1–3]. In a one-sided test procedure, thermal energy accumulates over low–heat-conducting defects of a large lateral area and leads to local temperature anomalies of significant amplitude against the background of a general increase in the temperature of the test object. Cracks, including those “kissing,” are effectively detected using stimulation by low-power ultrasonic-frequency mechanical vibrations generated, for example, by magnetostrictive transducers; this is the so-called ultrasonic infrared thermography (UIT) [4–7]. The friction of crack edges and fiber ruptures generate thermal energy that, in turn, leads to the emergence of local temperature signals but does not change temperature in defect-free areas. Combining different heating techniques can improve the efficiency of thermal quality inspection of products, in particular, of complex-shaped ones [8–10]. Thermal flaw detectors for combined thermal testing can be placed on robotic manipulators for monitoring single-type products in an automated mode [11–13]. When ultrasonic infrared testing is employed, the robot maintains reliable contact of magnetostrictive transducer’s indenter with the test object, thus improving the quality of the tests and ensuring their repeatability, difficult to achieve in manual mode. Testing complex-shaped products requires ultrasonic stimulation at several points, for example, arranged into a spatial grid with a certain step [14]. These requirements for ultrasonic infrared testing are due to the complex wave propagation and damping mechanisms, depending on the geometry of the object under study. One of the known techniques is to combine the results of opt
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