Micromechanics of Polycrystals: Full-field Computations and Second-order Homogenization Approaches
30 May 2012 | Online Presentations | Contributor(s): Ricardo Lebensohn
In the first part of this talk we will present a spectral formulation based on crystal plasticity and Fast Fourier Transforms (FFT) for the determination of micromechanical fields in plastically-deformed 3-D polycrystals. This formulation, pioneered by Suquet and coworkers as a fast algorithm to compute the response of composites using as input a digital image of the microstructure, has been in turn adapted to deal with polycrystals deforming by dislocation glide.
Next, the FFT-based formulation will be used to assess the accuracy of different available nonlinear homogenization approaches for the prediction of the viscoplastic behavior of polycrystalline aggregates. We will show that Ponte Castañeda’s second-order formulation, which explicitly uses information on average intragranular field fluctuations, implemented within the widely-used ViscoPlastic Self-Consistent (VPSC) code, yields the most accurate results.