eigfem.asv

结构力学中的有限元例子,包含了7个分类文件夹

function [G_fact, eig_vect, eig_V] = eigFEM (K, M, damp)

% eigFEM
% ---------------------------------------------------------------------
% eigenvalues and eigenvectors for stiffness & mass matrix " K ", " M "
% INPUT:
%       K           - stiffness matrix
%       M           - mass matrix
%       damp        - modal damping vector
% OUTPUT:
%       G_fact     - participation factor matrix
%       eig_vect   - matrix of eigen vectors
%       eig_V      - eigen values
%
% 2006
% ---------------------------------------------------------------------

% eigen values and vectors calculation -------------------------------
[eig_vect, eig_val]=eig(K,M);
eig_val=sqrt(real(eig_val));

eig_V=diag(eig_val);
eig_vect=real(eig_vect);

D = length(damp);               % # of dof's 

NOM=0; DIN=0;
for k=1:D
   for i=1:D
      NOM=M(i,i)*eig_vect(i,k)+NOM;
      DIN=M(i,i)*eig_vect(i,k)*eig_vect(i,k)+DIN;
   end;
   G(k)=-NOM/DIN;
   NOM=0; DIN=0;
end;
[eig_V, indx]=sort(eig_V,'descend');
eig_vect = (eig_vect(:,indx));
G_fact = G(indx);