In this talk, a computational method used to simulate the local and global response of composites with complex microstructure will be presented. It makes direct use of digital images of the microstructures under consideration and is based on the Fast Fourier transform. Connections with the Phase Field Method will be briefly discussed.
This method has been applied to investigate the response of nonlinear materials with various behaviours such as elastoplasticity of composites or polycrystals. The numerical simulations shed light on the accuracy of theoretical estimates for nonlinear composites.