Quantification of Shear Wave Scattering From Far-Surface Defects via Ultrasonic Wavefield Measurements

Area of Science:

• Materials Science
• Mechanical Engineering
• Non-Destructive Evaluation (NDE)

Background:

• Nondestructive evaluation (NDE) relies on understanding ultrasonic wave interactions with material defects.
• Wavefield imaging visualizes subsurface scatterer effects on surface wave motion.

Purpose of the Study:

• To visualize and quantify ultrasonic wave scattering from a far-surface corner notch in a plate.
• To analyze the influence of notch size and wave type (Rayleigh, shear, longitudinal) on scattering patterns.

Main Methods:

• Utilized angle-beam ultrasonic inspection with obliquely incident shear waves.
• Employed laser vibrometry and a scanner to record out-of-plane surface motion.
• Applied baseline subtraction and frequency-wavenumber domain filtering to isolate and analyze scattered wavefields.

Main Results:

• Successfully isolated scattered waves from incident and hole-scattered waves.
• Separated and analyzed Rayleigh, shear, and longitudinal wave contributions to scattering.
• Quantified scattering profiles for various notch sizes and transducer orientations.

Conclusions:

• Wavefield imaging effectively visualizes ultrasonic wave scattering from notches.
• Scattering characteristics vary with notch size and wave mode, providing data for NDE.
• The method offers a pathway to enhanced defect characterization in materials.