eldia2.m

基于matlab的有限元程序源代码

function [magnfac]=eldia2(ex,ey,es,eci,magnfac,magnitude)
%[magnfac]=eldia2(ex,ey,es,eci)
%eldia2(ex,ey,es,eci,magnfac,magnitude)
%eldia2(ex,ey,es,eci,magnfac)
%
%-------------------------------------------------------------
% PURPOSE: 
%  Draw the section force diagrams of a two dimensional beam element.
%  	
% INPUT:
%	ex = [ x1 x2 ]
%	ey = [ y1 y2 ]	element node coordinates.
%
%	es = [  X1;
%		X2;
%		... ] 	vector containing the section force
%			in Nbr evaluation points along the beam.
%	
%	eci = [	x1;
%		x2;
%		... ]	local x-coordinates of the evaluation points (Nbr).
%
%	magnfac = [scalar]	magnification factor.
%	
%	Rem. if magnfac is omitted in the input list it is calculated
%            as an output parameter.
%
%	magnitude = [Ref x y]	Draw a scaled bar, with a lenth equivalent   
%				to Ref, starting at coordinates (x,y).
%				If no coordinates are given the starting
%				point will be (0,-0.5).
%
%	Rem. if magnitude is omitted in the input no scaled bar is provided.
%
%-------------------------------------------------------------

% LAST MODIFIED: A Olsson 	1999-03-01
% Copyright (c)  Division of Structural Mechanics and
%                Department of Solid Mechanics.
%                Lund Institute of Technology
%-------------------------------------------------------------

if ~((nargin==4)|(nargin==5)|(nargin==6))
    disp('??? Wrong number of input arguments!')
    break
 end
a=size(ex); b=size(ey);
 
 if ~((a-b)==[0 0])
    disp('??? Check size of coordinate input arguments!')
    break
 end
c=size(es);
a=size(eci); 
 if ~(c(1)==a(1)|(c(2)==1))
    disp('??? Check size of "es" or "eci" input arguments!')
    break 
 end 
b=[ex(2)-ex(1);ey(2)-ey(1)];
Length=sqrt(b'*b);
n=b/Length;
if nargin==4
	% Determining magnfac.
	magnfac=max(abs(es))/(0.2*Length);
else
        hold on
end
es=es/magnfac;
if nargin>5
	% Creating a scaled bar.
	N=magnitude(1);
	L=N/magnfac;
	mag=size(magnitude);
	if mag(2)==1
		x=0;
		y=-0.5;
	else
		x=magnitude(2);
		y=magnitude(3);
	end;
	line([x (x+L)],[y y]);
	line([x x],[(y-L/20) (y+L/20)]);
	line([(x+L/2) (x+L/2)],[(y-L/20) (y+L/20)]);
	line([(x+L) (x+L)],[(y-L/20) (y+L/20)]);
	text((N*1.1)/magnfac+x,y,sprintf('%4.0f ', N));
end
% From local x-coordinates to global coordinates of the beam element.
An=size(eci);
Nbr=An(1);
A=zeros(Nbr,2);
A(1,1)=ex(1);
A(1,2)=ey(1);
for i=2:Nbr
	A(i,1)=A(1,1)+eci(i)*n(1);
	A(i,2)=A(1,2)+eci(i)*n(2);
end

B=A;
for i=1:Nbr
	A(i,1)=A(i,1)+es(i)*n(2);
	A(i,2)=A(i,2)-es(i)*n(1);
end
% Type is set to 0 by default.
pl=0;
if nargin==4
	% Do not plot if input arguments are missing.
	pl=3;
end
if pl==0
	% Plots striped diagrams.
	for i=1:Nbr
		line([B(i,1) A(i,1)],[B(i,2) A(i,2)]);
	end
end
if pl<3
	line(A(:,1),A(:,2));
	line([ex(1) A(1,1)],[ey(1) A(1,2)]);
	line([ex(2) A(Nbr,1)],[ey(2) A(Nbr,2)]);
	
	a=plot(ex',ey','-r');
	set(a,'LineWidth',[2]);
	set(gca,'FontSize',[10]);
	
end
hold off;