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Published on: March 2, 2020
Numerical model of longitudinal wave scattering in polycrystals
Goutam Ghoshal1, Joseph A Turner
1Department of Engineering Mechanics, University of Nebraska-Lincoln, Lincoln, NE, USA.
Summary
Numerical simulations using Voronoi polycrystals validate ultrasonic scattering models for materials characterization. This research enhances nondestructive evaluation (NDE) by comparing simulation results with scattering theory, revealing frequency-dependent correlations.
Area of Science:
- Materials Science
- Acoustics
- Computational Mechanics
Background:
- Ultrasonic wave scattering in polycrystalline materials is crucial for materials characterization and nondestructive evaluation (NDE).
- Current scattering models often rely on simplifying assumptions (constant density, uniform grain size, ergodicity) that limit experimental validation.
- Practical limitations in real material processing hinder comprehensive experimental testing of these models' accuracy and applicability.
Purpose of the Study:
- To address the limitations in experimentally validating ultrasonic scattering models for polycrystalline materials.
- To investigate wave propagation and scattering phenomena using numerical simulations.
- To compare simulation results with established scattering theories across a range of frequencies.
Main Methods:
- Utilized numerical simulations employing finite element discretization of Voronoi polycrystals.
- Studied elastic wave propagation by direct time integration with a plane strain formulation.
- Generated statistically isotropic bulk material using Voronoi polycrystals with cubic symmetry and random orientations.
Main Results:
- Presented numerical results for materials exhibiting varying degrees of scattering.
- Demonstrated good agreement between numerical simulation outcomes and scattering theory for examined cases.
- Provided evidence for a frequency-dependent correlation function in elastic wave scattering.
Conclusions:
- The study validates the use of numerical simulations with Voronoi polycrystals for studying ultrasonic wave scattering.
- Findings support and refine existing scattering theories, highlighting the frequency dependence of correlation functions.
- Anticipated impact on the field of ultrasonic nondestructive evaluation (NDE) for polycrystalline media.
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