Structural Health Monitoring with Piezoelectric Wafer Active Sensors, 2nd Edition

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where $J_1$ is the Bessel function of the first kind and order 1, and $H_1^{(1)}$ is the Hankel function of the first kind and order 1. The summation is taken over all the symmetric, ${\xi }^S$, and antisymmetric, ${\xi }^A$, Lamb wave modes that exist at a given frequency ...