Simulation of ultrasonic array imaging of composite materials with defects

Area of Science:

• Materials Science
• Nondestructive Evaluation
• Ultrasonic Testing

Background:

• Ultrasonic transducer arrays are vital for nondestructive evaluation (NDE) in aerospace.
• Composite materials present challenges for ultrasonic testing due to reflections, attenuation, and anisotropy.
• Full matrix capture (FMC) mode with total focusing method (TFM) requires algorithm refinement for composites.

Purpose of the Study:

• To develop and validate a simulation model for ultrasonic array signals in multilayer anisotropic composites.
• To investigate the impact of anisotropy, signal-to-noise ratio, and aperture limits on imaging algorithm performance.
• To facilitate the development of improved imaging algorithms for defect detection in composites.

Main Methods:

• Simulations of ultrasonic array signals in multilayer anisotropic materials with and without defects.
• Modeling full array signals using a kernel model for plane wave propagation, angular spectrum decomposition, and transducer frequency response.
• Incorporating defect scattering response through far-field scattering.

Main Results:

• The developed model accurately simulates ultrasonic array signals in complex composite structures.
• Identified the significant effects of material anisotropy and aperture limits on imaging quality and defect localization.
• Demonstrated an analytical method for calculating effective group velocity for practical time delay laws.

Conclusions:

• The simulation model is crucial for understanding and improving ultrasonic imaging algorithms for composite materials.
• Addressing anisotropy and optimizing aperture are key to enhancing signal-to-noise ratio and defect detection accuracy.
• The presented analytical method enables faster implementation of ultrasonic testing in composite NDE.