Loop is not running in Matlab

I`m trying to update the variables inside the loop .

I`m sypposed to get a plot where stress and strain respectively as x and y coordinates.Unfortunately i got nothing at all.

Please help.

clc;clear;
%disp('................................Concrete properties');
Fcu=0.3;                  %input('Ultimate compressive strength(t/cm2)');
Ec=240.9;                 % Modulus of Elasticity
u=0;                      % Strain at oroginal point
s=0;                      %Stress aat original point
uy=-Fcu/Ec;               % uy  is the concrete strain corresponding to ultimate stress.
%number of steps for strain increment=150
%%%%%%%%%%%% Elastic Branch  %%%%%%%%%%%%%%%%%%%
for i=0.0015:-0.0015:0.00001;                %deltau is strian increment
    if deltau(i)<0 && deltau(i)<uy
       factor=(-uy-u(i))/deltau(i);
           if factor>1.0                               %Elastic Branch
            E(i)=Ec;
            u(i)=u(i)+deltau(i);
            s(i)=s(i)+deltau(i)*Ec;
          end
        Array=[u(i),s(i)]
        plot(u(i),s(i))
        hold on

Answer 1

[Stijn Haenen]

There are some errors in your script:

i=0.0015:-0.0015:0.00001;

Only gives the number 0.0015 as output, if you want that i goes from -0.0015 to 0.0015 with steps of 0.00001 use:

i=-0.0015:0.00001:0.0015.

in your for loop i is not an integer so you cannot use deltau(i), the same hold for u(i) and s(i).

maybe you should use this:

i_list=-0.0015:0.00001:0.0015
for i=1:numel(i_list)
    ...
end

and two 'end' commands are missing in your script.

[Flower Rose]

Stijn Haenen

Thx for your reply,,

I changed the code as you suggested .Where delta u is a strain increment from( -.0015,-.00149,-.00148.......0.0015) .That`s why i put i in the first place.

Unfortunately,,it gives me error Index exceeds matrix dimensions.

Any thoughts?

Plus,is u=0 and s=0 as intial values iare at the right place in the code?.Beacuse when i tried to remove them,i got undefined function or variable.

P.S ,As (for the two end ),,i have two other loops under the presented one.So i extracted this loop to find out what is wrong.

clc;clear;
%disp('................................Concrete properties');
Fcu=0.3;                  %input('Ultimate compressive strength(t/cm2)');
Ec=240.9;                 % Modulus of Elasticity
u=0;                      % Strain at oroginal point
s=0;                      %Stress aat original point
uy=-Fcu/Ec;               % uy  is the concrete strain corresponding to ultimate stress.
%number of steps for strain increment=150
%%%%%%%%%%%% Elastic Branch  %%%%%%%%%%%%%%%%%%%
i_deltau=-0.0015:0.00001:0.0015;                %deltau is strian increment
for i=1:numel(i_deltau)
    if i<0 && i<uy
       factor=(-uy-u(i))/i;
           if factor>1.0                               %Elastic Branch
            E(i)=Ec;
            u(i)=u(i)+i;
            s(i)=s(i)+i*Ec;
           end
    end
end
        Array=[u(i),s(i)]
        plot(u(i),s(i))
        hold on