Behavior of Ao Mode Transduced Using Synchronised Rotationally (Same Direction) Misaligned Air-coupled Transducers

Transmission and reception of single selective Lamb mode is feasible using air-coupled ultrasonic transducers. However, alignment of air-coupled probes influences amplitude of Lamb mode. Properly oriented and aligned air-coupled probes satisfy Snell's law and coplanarity condition. This results in transduction of high amplitude Lamb waves. In this work, a misalignment termed ‘synchronized (same direction) rotational misalignment’ was introduced between the air-coupled transducers in isotropic plates. It was found from experiments that, due to the misalignment, variation in normalised amplitude of the fundamental anti-symmetric Lamb mode (Ao) with respect misalignment angle follows Gaussian fit.