Validation of Temperature Compensation Techniques for Impact Damage Detection and Localization Using Ultrasonic Sparse Arrays
Abstract
Within this paper the authors implemented and tested three different methods for temperature compensation Ð best baseline approach, signal interpolation and frequency shift Ð on thin monolithic composite plates and composite honeycomb panels together with the effectiveness of the different approaches for damage detection and localization under varying temperature conditions using sparse array configurations. The effectiveness of the different procedures have been compared and ranked. The best suited procedure Ð the frequency shift approach using the closest baseline measurement Ð was implemented in virtual beam forming algorithm used to visualize the ultrasonic image of the structure. Experiments have been conducted on an 800 x 800 mm² honeycomb panel instrumented with 4 piezo actuators and 8 piezo sensors. Different baseline measurements at various temperatures have been compared against measurement after the application of artificial damages using the best suited temperature compensation technique. It could be shown that temperature differences of several degrees between the baseline measurement and the measurement after damage introduction completely hides the appearance of the damage without using temperature compensation techniques. On the other hand all damages could be successfully detected and located when applying the proposed temperature compensation technique.
Origin : Files produced by the author(s)
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