The multi-modal dispersive nature of ultrasonic guided waves makes it difficult to interpret received signals to locate defects or reflectors in plates and pipes.  Depending on the type of inspection, there are multiple approaches to solve this problem.  Often times, inspections are performed using low frequencies where the dispersive behavior is minimal and only the first two fundamental modes are excited.  Work presented by the authors at the QNDE 2019 conference successfully demonstrated a method of source location which removed the delterious effects of dispersion regardless of the frequency of operation or number of modes generated.  The current work builds on last year's progress by extending the method to pitch-catch source location.  A novel 64 element phased array from Imasonic is placed on the top surface of a 2 mm aluminum plate.  Guided waves are excited by phasing array elements to produce approximately planar wavefronts at 64 different angles.  Obtaining measurements for the resulting 4096 combinations of transmit and receive angles allows individual mode reflection coefficients to be computed via a variational method.  After individual mode reflection coefficients are known, the location of the edge is revealed by 'back-propagating' the expression for particle displacement.   Presented in this abstract is a detailed discussion of the algorithm for array based pulse-echo source location as well as results for an application of the method to synthetically generated data.  Results shown successfully demonstrate the viability of the method.  Additional work to be presented at the 2020 QNDE conference will include experimental data obtained using the measurement setup presented in this abstract.  


Array Based Guided Wave Transduction With Pulse-Echo Source Location Using Dispersion Compensation

No proceedings papers in 2020. Video only.

QNDE2020 - Virtual Conference

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