assemble.m

matlab实例

%***********************************************************************
%  function assemble
%
%  assembly of element stiffness matrices into global stiffness matrix
%    based on nodal connectivity matrix
%***********************************************************************
function [kglobal, load_vector] = assemble(kelem, felem, ElemData,ElemType, kglobal, load_vector)

elemType = ElemData.elemType;
nnodes   = ElemType(elemType).nnodes;
ndofs_node = ElemType(elemType).ndofs_node;

% NOTE: assuming (by using ndofs_node) that all nodes have the same number of dofs!
for inode = 1:nnodes
  irow   = ndofs_node * (ElemData.connect(inode) - 1) + 1;
  irow_e = ndofs_node * (inode - 1) + 1;
  load_vector(irow:irow+ndofs_node-1) = load_vector(irow:irow+ndofs_node-1) + felem(irow_e:ndofs_node*inode);
  for jnode = 1:nnodes
      jcol   = ndofs_node * (ElemData.connect(jnode) - 1) + 1;
      jcol_e = ndofs_node * (jnode - 1) + 1;     
      
      kglobal(irow : irow+ndofs_node-1, jcol : jcol+ndofs_node-1) = ...
          kglobal(irow : irow+ndofs_node-1, jcol : jcol+ndofs_node-1) + ...
           kelem(irow_e : ndofs_node*inode, jcol_e : ndofs_node*jnode);
  end
end