Numerical and analytic modelling of elastodynamic scattering within polycrystalline materials

Area of Science:

• Solid Mechanics
• Materials Science
• Acoustics

Background:

• Understanding wave propagation in polycrystalline materials is crucial for material characterization and non-destructive testing.
• Existing analytical models often simplify the complex scattering phenomena occurring in these heterogeneous media.

Purpose of the Study:

• To evaluate and compare different analytical models for predicting elastodynamic behavior (wave speed and attenuation) of longitudinal waves in polycrystalline cubic materials.
• To validate analytical predictions against numerical simulations and experimental data.

Main Methods:

• Developed a three-dimensional Finite Element (FE) model for full-physics simulation of wave scattering.
• Compared FE results with predictions from the Far-Field Approximation (FFA), Self-Consistent Approximation (SCA), and a new Second Order Approximation (SOA) model.
• Included the Stanke and Kino model for comparative analysis.

Main Results:

• The Second Order Approximation (SOA) model demonstrated excellent agreement with Finite Element (FE) simulations across various parameters.
• The Far-Field Approximation (FFA) provided a satisfactory approximation, though less accurate than SOA.
• Experimental wave velocity data showed better agreement with SOA and SCA when a Voigt reference was used.

Conclusions:

• The Second Order Approximation (SOA) is a highly accurate model for predicting elastodynamic behavior in polycrystalline materials.
• Full-physics numerical simulations are essential for validating and refining analytical models.
• Accurate representation of length-scale distributions is critical for predicting wave scattering behavior.