Within Fenics what ordering is used for storing vectors as upper triangular matrices? Th:e question really is I define a green Lagrange strain tensor in the following way:
V = VectorFunctionSpace(mesh, "Lagrange", 1) u = Function(V) I = Identity(V.cell().d) # Identity tensor F = I + grad(u) # Deformation gradient C = F.T*F # Right Cauchy-Green tensor E = (C-I)/2 #green strain tensor
But when I accesses the elements later,
psi = stress1*E[0,0]+stress2*E[1,1]+stress3*(E[2,2])+stress4*E[1,2]+stress5*E[0,2]+stress6*E[0,1]
I assumed Voigt notation but it occurs to me that this may not be the case. Using this method to initialize the strain tensor is this the notation I should be using or is there a different type or initialization that would be more appropriate?
Thanks for any help.