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Defect detection and characterization are critical tasks for structural health monitoring of engineering structures. Physical aging during routine operation promotes deterioration and generates hidden internal and/or superficial defects in these structures. Thus detection during service is of critical importance. In this work, the Lamb wave's propagation behavior in helical paths around hollow cylinders is theoretical and experimentally studied. A ray-tracing algorithm is implemented to improve theoretical estimation of signal travel path and time of flight. A study investigating the generation and detection of Lamb waves using a pulsed Laser and a photo-EMF detector is presented. The interaction of Lamb waves with imperfect contact conditions between two hollow cylinders in axial mechanical contact is also studied. Additionally, ultrasonic tomography of defects in cylinders is achieved by implementing the algebraic reconstruction technique (ART algorithm). The use of Lamb waves traveling in multiple helical paths around the hollow cylinder is proposed to improve the tomography reconstruction's quality with a limited number of captured signals and transmitter-receiver positions.
About the author
Antonio Balvantin is currently a professor in the Department of Mechanical Engineering at the University of Guanajuato, Mexico. He has published multiple research papers in conferences and journals related to Quantitative Nondestructive Evaluation (QNDE) of materials using ultrasound, mechanical design, instrumentation and mechanics of interfaces.
