option to initialize F_i

start simulation with eigenstrain. Works only for moderate
eigentstrains, reaching the plastic limit is most likely an issue.

src/material.f90

@@ -26,6 +26,7 @@ module material
 
 
   type(tRotationContainer), dimension(:), allocatable :: material_O_0
+  type(tTensorContainer),   dimension(:), allocatable :: material_F_i_0
 
   integer, dimension(:), allocatable, public, protected :: &
     homogenization_Nconstituents                                                                    !< number of grains in each homogenization
@@ -48,6 +49,7 @@ module material
   public :: &
     tTensorContainer, &
     tRotationContainer, &
+    material_F_i_0, &
     material_O_0, &
     material_init
 
@@ -159,14 +161,17 @@ subroutine parse()
   enddo
 
   allocate(material_O_0(materials%length))
+  allocate(material_F_i_0(materials%length))
 
   do ma = 1, materials%length
     material     => materials%get(ma)
     constituents => material%get('constituents')
     allocate(material_O_0(ma)%data(constituents%length))
+    allocate(material_F_i_0(ma)%data(1:3,1:3,constituents%length))
     do co = 1, constituents%length
       constituent => constituents%get(co)
       call material_O_0(ma)%data(co)%fromQuaternion(constituent%get_as1dFloat('O',requiredSize=4))
+      material_F_i_0(ma)%data(1:3,1:3,co) = constituent%get_as2dFloat('F_i',defaultVal=math_I3) ! requiredShape=(3,3)
     enddo
  enddo
 

src/phase_mechanical.f90

@@ -206,6 +206,9 @@ module subroutine mechanical_init(materials,phases)
     phases
 
   integer :: &
+    ce, &
+    co, &
+    ma, &
     ph, &
     en, &
     Nmembers
@@ -262,15 +265,21 @@ module subroutine mechanical_init(materials,phases)
 #endif
   enddo
 
+  do ce = 1, size(material_phaseID,2)
+    ma = discretization_materialAt((ce-1)/discretization_nIPs+1)
+    do co = 1,homogenization_Nconstituents(material_homogenizationID(ce))
+      ph = material_phaseID(co,ce)
+      phase_mechanical_Fi0(ph)%data(1:3,1:3,material_phaseEntry(co,ce)) = material_F_i_0(ma)%data(1:3,1:3,co)
+    enddo
+  enddo
+
   do ph = 1, phases%length
     do en = 1, count(material_phaseID == ph)
 
       phase_mechanical_Fp0(ph)%data(1:3,1:3,en) = phase_O_0(ph)%data(en)%asMatrix()                 ! Fp reflects initial orientation (see 10.1016/j.actamat.2006.01.005)
       phase_mechanical_Fp0(ph)%data(1:3,1:3,en) = phase_mechanical_Fp0(ph)%data(1:3,1:3,en) &
                                                 / math_det33(phase_mechanical_Fp0(ph)%data(1:3,1:3,en))**(1.0_pReal/3.0_pReal)
-      phase_mechanical_Fi0(ph)%data(1:3,1:3,en) = math_I3
-      phase_mechanical_F0(ph)%data(1:3,1:3,en)  = math_I3
-
+      phase_mechanical_F0(ph)%data(1:3,1:3,en) = math_I3
       phase_mechanical_Fe(ph)%data(1:3,1:3,en) = math_inv33(matmul(phase_mechanical_Fi0(ph)%data(1:3,1:3,en), &
                                                                    phase_mechanical_Fp0(ph)%data(1:3,1:3,en)))  ! assuming that euler angles are given in internal strain free configuration
     enddo