"Subscripted assignment dimension mismatch"

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Pavlin
Pavlin 2012-11-15
Hello,
Here is part of the code in which I can't avoid the following error: "Subscripted assignment dimension mismatch" at line 115. I do not have this error and the code runs fine, when I take away the main loop for the incremental load and instead have just one predefined value. If anyone can help, I will highly appreciate! If necessary I will send the whole code by mail.
Regards, Pavlin
CODE
for increment = 1:incmax
q_total=q_total+q_incr;
K(beam_DOFs,beam_DOFs)=0;
F(beam_DOFs,1)=0;
for el_y=1:beam_el_y
y1=(W/beam_el_y)*(el_y-1);
y3=y1+W/beam_el_y;
for el_x=1:beam_el_x
x1=(L/beam_el_x)*(el_x-1);
x3=x1+L/beam_el_x;
i1=(beam_el_y+1)*(el_x-1)+el_y;
i2=i1+beam_el_y+1;
el_DOFs=[2*i1-1; 2*i1 ; 2*i2-1 ; 2*i2; 2*i2+1; 2*i2+2; 2*i1+1; 2*i1+2];
Em=(E_el(el_x,el_y)/(1-nu^2))*[1 nu 0
nu 1 0
0 0 (1-nu)/2];
Ke=Q4_stiffness(x1,x3,y1,y3,Em,T);
K(el_DOFs,el_DOFs)=K(el_DOFs,el_DOFs)+Ke;
end
end
all_DOFs=1:beam_DOFs;
fixed_DOFs_y=beam_DOFs;
fixed_DOFs_x=1:2:2*(beam_el_y+1);
fixed_DOFs=union(fixed_DOFs_x,fixed_DOFs_y);
free_DOFs=setdiff(all_DOFs,fixed_DOFs);
F(2,1)=-q_total;
U(free_DOFs,:)=K(free_DOFs,free_DOFs)\F(free_DOFs,:);
U(fixed_DOFs,:)=0;
ver_DOFs_top_side=2*(beam_el_y+1):2*(beam_el_y+1):beam_DOFs;
U(ver_DOFs_top_side,:);
ver_DOFs_top_side2=ver_DOFs_top_side;
ver_DOFs_top_side2(:,end)=[];
U(2,1);
U_tot=U_tot+U(2,1);
for el_y=1:beam_el_y
y1=(W/beam_el_y)*(el_y-1);
y3=y1+W/beam_el_y;
for el_x=1:beam_el_x
x1=(L/beam_el_x)*(el_x-1);
x3=x1+L/beam_el_x;
i1=(beam_el_y+1)*(el_x-1)+el_y;
i2=i1+beam_el_y+1; % i2=(DCB_y+1)*el_x+el_y;
el_DOFs=[2*i1-1; 2*i1 ; 2*i2-1 ; 2*i2; 2*i2+1; 2*i2+2; 2*i1+1; 2*i1+2];
Em=(E_el(el_x,el_y)/(1-nu^2))*[1 nu 0
nu 1 0
0 0 (1-nu)/2];
el_displ=U(el_DOFs);
el_stress=zeros(3,8);
el_strain=zeros(3,8);
[el_stress el_strain]=Q4_stress(x1,x3,y1,y3,Em,el_displ);
Sigma_xx(el_x,el_y)=el_stress(1,1);
Sigma_yy(el_x,el_y)=el_stress(2,1);
Sigma_xy(el_x,el_y)=el_stress(3,1);
x(el_x,el_y)=x1; % For the mesh plot
y(el_x,el_y)=y1; % For the mesh plot
Sigma_xx_tot(el_x,el_y) = Sigma_xx_tot(el_x,el_y) + Sigma_xx(el_x,el_y);
Sigma_yy_tot(el_x,el_y) = Sigma_yy_tot(el_x,el_y) + Sigma_yy(el_x,el_y);
Sigma_xy_tot(el_x,el_y) = Sigma_xy_tot(el_x,el_y) + Sigma_xy(el_x,el_y);
S11 = 2*Sigma_xx_tot(el_x,el_y)/3 - Sigma_yy_tot(el_x,el_y)/3;
S22 = 2*Sigma_yy_tot(el_x,el_y)/3 - Sigma_xx_tot(el_x,el_y)/3;
S12 = Sigma_xy_tot(el_x,el_y);
Sigma_von_Mises = sqrt(3*(S11^2+S22^2+3*S12^2)/2);
if Sigma_von_Mises > Sigma_y;
E_el(el_x,el_y)=E/10;
else
E_el(el_x,el_y)=E;
end
end
end
last_x=zeros(1,beam_el_y);
LINE 115 last_x(1,:)=x(end,:)+L/beam_el_x;
x=[x;last_x]; x=[x,x(:,end)]; last_y=zeros(1,beam_el_y); last_y(1,:)=y(end,:); y=[y;last_y]; y=[y,y(:,end)+W/beam_el_y];

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采纳的回答

Matt Fig
Matt Fig 2012-11-15
编辑：Matt Fig 2012-11-15
This error occurs, much like the message tells you, when you try to put the wrong number (or shape) of items into an array. Here is a simple example:
H = zeros(6);
try
H(:,1) = rand(2,3); % Wrong shape.
catch
fprintf('%s\n',lasterr)
end
try
H(:,1) = rand(7,1); % Wrong number.
catch
fprintf('%s\n',lasterr)
end
H(:,1) = rand(6,1) % Correct shape and number!
  1 个评论
Pavlin
Pavlin 2012-11-15
Thanks,
I knew how it works, but what I had not taken into consideration is that x changes dimension after some convergence is executed by another file. Then, this function is called again and I have to clear the x value before it. The function will regenerate it again in with the correct form.

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