Wenk 9417580 The proposal is to investigate ductile deformation of polymineralic rocks and accompanying development of preferred orientation and anisotropy. Finite element methods will be used to model deformation of crystal aggregates at the submicroscopic intragrain scale and compare results with analytical upper and lower bounds solutions. Based on results constitutive equations for deformation of plastically anisotropy and heterogeneous polymineralic rocks can be proposed. FEM methods will also be used to model large heterogeneous systems such as convection of the Earth's mantle, with more realistic geometry and material constraints than in a preliminary pilot study. Instead of using a single number for viscosity to describe the material behavior as is done in classical isotropic convection studies, each element will contain an assembly of 500 grains and deform according to principles of strain compatibility and stress equilibrium. These models of anisotropy convection based on polycrystal plasticity concepts will be useful for geodynamics and seismology to understand development and interpretation of anisotropy of elastic waves. ****
