exs3.m

用于在matlab平台上进行有限元分析

% example exs3 
%----------------------------------------------------------------
% PURPOSE 
%    Analysis of a plane truss.
%----------------------------------------------------------------

% REFERENCES
%     Ola Dahlblom 2004-09-07 
%----------------------------------------------------------------

echo on 

%----- Topology matrix Edof -------------------------------------

 Edof=[1   1  2  5  6;
       2   5  6  7  8;
       3   3  4  5  6];
 
%----- Stiffness matrix K and load vector f ---------------------

 K=zeros(8); 
 f=zeros(8,1);	f(6)=-80e3;

%----- Element properties ---------------------------------------
 
 E=2.0e11;
 A1=6.0e-4;     A2=3.0e-4;     A3=10.0e-4;
 ep1=[E A1];    ep2=[E A2];    ep3=[E A3];	
 

%----- Element coordinates --------------------------------------

 ex1=[0 1.6];    ex2=[1.6 1.6];    ex3=[0 1.6];   
 ey1=[0 0];      ey2=[0 1.2];      ey3=[1.2 0];   
 
%----- Element stiffness matrices  ------------------------------

 Ke1=bar2e(ex1,ey1,ep1)	 
 Ke2=bar2e(ex2,ey2,ep2)
 Ke3=bar2e(ex3,ey3,ep3)	
 
%----- Assemble Ke into K ---------------------------------------

 K=assem(Edof(1,:),K,Ke1);
 K=assem(Edof(2,:),K,Ke2); 
 K=assem(Edof(3,:),K,Ke3)	
 
%----- Solve the system of equations ----------------------------

 bc= [1 0;2 0;3 0;4 0;7 0;8 0];   
 [a,r]=solveq(K,f,bc)

%----- Element forces -------------------------------------------

 ed1=extract(Edof(1,:),a);
 N1=bar2s(ex1,ey1,ep1,ed1)
 ed2=extract(Edof(2,:),a);
 N2=bar2s(ex2,ey2,ep2,ed2)
 ed3=extract(Edof(3,:),a);	
 N3=bar2s(ex3,ey3,ep3,ed3)
 
%---------------------------- end -------------------------------
 echo off