Recent advances in Fast Fourier Transform (FFT)-based models for microstructure/property relationships of polycrystalline materials

Crystal plasticity (CP) are well-established models, used, e.g., in scale-bridging applications to obtain microstructure-sensitive mechanical response of polycrystalline materials. These models require a proper consideration of the single crystal deformation mechanisms, a representative description of the microstructure, and an appropriate scheme to connect the microstates with the macroscopic response. FFT-based methods, originally proposed by Moulinec and Suquet for composites [1] and extended to polycrystals [2] (our most recent formulation, including non-local large-strain elasto-viscoplasticity reported in [3]) are attractive due to their higher efficiency compared with CP-Finite Elements, and their direct use of voxelized microstructural images. In this talk, we will report recent progress on FFT-based polycrystal plasticity, with emphasis in novel implementations, including strain-gradient plasticity, achieving geometric accuracy working with voxelized images, non-periodic extensions, and dynamic effects. We will show applications of these methods to: micromechanics of nano-metallic laminates, wave propagation in heterogeneous materials, multiscale coupling with Lagrangian hydrocodes, and integration with 3-D characterization methods.

[1] Moulinec, H., Suquet, P., A numerical method for computing the overall response of nonlinear composites with complex microstructure. CMAME 157, 69, (1998).

[2] Lebensohn, R.A., N-site modelling of a 3D viscoplastic polycrystal using Fast Fourier Transform. Acta Mater. 49, 2723 (2001).

[3] Zecevic M., Lebensohn R.A., Capolungo L., Non-local large-strain FFT-based formulation and its application to interface-dominated plasticity of nano-metallic laminates. JMPS 173, 105187 (2023).