exs8.m

用于在matlab平台上进行有限元分析

% example exs8
%----------------------------------------------------------------
% PURPOSE 
%    Analysis of two dimensional diffusion
%----------------------------------------------------------------

% REFERENCES
%     Karl-Gunnar Olsson 1995-10-08
%     Ola Dahlblom 2004-09-14
%----------------------------------------------------------------
echo on

% ----- System matrices -----

K=zeros(15);	f=zeros(15,1);
Coord=[0     0    ; 0.025 0    ; 0.05  0    
       0     0.025; 0.025 0.025; 0.05  0.025
       0     0.05 ; 0.025 0.05 ; 0.05  0.05 
       0     0.075; 0.025 0.075; 0.05  0.075
       0     0.1  ; 0.025 0.1  ; 0.05  0.1  ];
Dof=[ 1; 2; 3
      4; 5; 6
      7; 8; 9
     10;11;12
     13;14;15];

% ----- Element properties, topology and coordinates -----

ep=1; D=[1 0;0 1];       
Edof=[1   1  2  5  4
      2   2  3  6  5
      3   4  5  8  7
      4   5  6  9  8
      5   7  8 11 10
      6   8  9 12 11
      7  10 11 14 13
      8  11 12 15 14];
[Ex,Ey]=coordxtr(Edof,Coord,Dof,4);

% ----- Generate FE-mesh -----

clf; eldraw2(Ex,Ey,[1 3 0],Edof(:,1));
disp('PRESS ENTER TO CONTINUE'); pause; clf;

% ----- Create and assemble element matrices -----

for i=1:8
  Ke=flw2qe(Ex(i,:),Ey(i,:),ep,D);
  K=assem(Edof(i,:),K,Ke);
end;

% ----- Solve equation system -----

bc=[1 0;2 0;3 0;4 0;7 0;10 0;13 0.5e-3;14 1e-3;15 1e-3];
[a,r]=solveq(K,f,bc)

% ----- Compute element flux vector -----

Ed=extract(Edof,a);
for i=1:8
  Es(i,:)=flw2qs(Ex(i,:),Ey(i,:),ep,D,Ed(i,:))
end

% ----- Draw flux vectors and contourlines -----

sfac=scalfact2(Ex,Ey,Es,0.5);
eldraw2(Ex,Ey,[1,3,0]); 
elflux2(Ex,Ey,Es,[1,4],sfac); 
pltscalb2(sfac,[2e-2 0.06 0.01],4);
disp('PRESS ENTER TO CONTINUE'); pause; clf;
eldraw2(Ex,Ey,[1,3,0]); 
eliso2(Ex,Ey,Ed,5,[1,4]);
hold off; 
echo off;

% ----------------- End --------------------------------