2.6 BRIDGING STRATEGIES FOR THE MACROSCALE AND THE MESOSCALE
Bridging of the mesoscale simulations to the macroscale models requires both the constraints defined by the macroscale ISV formulation first. However, the constraints from the macroscale ISV are a necessary but not sufficient condition to garner the exact information unless mesoscale results can be embedded into the ISV formalism. Hence, both downscaling and upscaling techniques are required.
2.6.1 Downscaling: Defining the Macroscale Constraints for the Mesoscale Analysis
Development of bridging methodology from the macroscale polycrystalline material to mesoscale single crystal or grain level is required for multiscale bridging. What is required in terms of plasticity, damage, and fatigue from the mesoscale includes the following:
1. yield surface shape information depending on the deformation path;
2. kinematic and isotropic hardening evolution information depending on the deformation path;
3. plastic spin evolution information depending on the deformation path;
4. coalescence evolution information of damage entities in the microstructure;
5. void growth evolution information arising from the damaged entities in the microstructure;
6. void nucleation evolution information regarding debonding and fracture of particles in the microstructure;
7. crystal orientation relationships with local plastic shear strain ranges for incubation of fatigue cracks.
8. crystal orientation relationships with crack tip opening displacements ...