matlab - Assembly stiffness matrix for materials -

i working on fem elastic plane strain problem. need use 3 different materials , having difficulties assembly of stiffness matrix.

here little cod of assembly 1 type of material:

edof = length(index);   % dof per element (x,y)  = 1:edof     ii = index(i);      j = 1:edof         jj = index(j);         k(ii,jj) = k(ii,jj) + k(i,j);    % k elem stiffness matrix     end  end 

suggestions welcomed.

if want use finite element method first need find finite subspace v of hilbert-1 space (with compact support).

let differential operator of problem. stiffness matrix suffices:

a(i,j) = a(phi(i),phi(j))

where phi(i)and phi(j) elements of v (your subspace).

with lecture notes learnt fem methods (page 23 explain above in more detail), here find more notes numerical pdes.

hope helps.