Guided Shear Horizontal (SH) Wave Electromagnetic Acoustic Transducer (EMAT) for In-situ Nondestructive Inspection of Ice and Cracks

We propose a novel and integrated approach to inspect the ice and cracks in aircraft structures. It combines the state-of-the-art SH wave EMAT technique, through detailed numerical modeling and instrumentation for data collection, with our record-proven advanced signal processing and pattern classification technique, to detect and characterize the ice and crack problems. The technique has four components: (1) thorough guided wave modal analysis, (2) recently developed two-dimensional (2D) and 3D Boundary Element Method (BEM) for best operational condition selection and defect feature extraction, (3) ultrasonic Shear Horizontal (SH) waves EMAT sensor design and data collection, and (4) advanced signal processing algorithm like nonlinear split-spectrum filter, Principal Component Analysis (PCA) and Learning Vector Quantization (LVQ) for signal-to-noise-ratio enhancement, ice/crack signature extraction, and pattern classification. The proposed system is supported with solid physics models and our innovative statistical signal processing algorithms. It is expected to achieve ultra reliable self-diagnosis capability.