how to plot values that are used in iteration

numberofdisc= input('please enter number of disc in your system=');

x = input('please enter lower value of total torque=');

y = input('please enter higher value of total torque=');

Wn = input ('Please enter beginning frequency value to calculate natural frequency (rad/s)=');

Wnf = input ('Please enter differences between iterasion values=');

Wns = input ('Please enter last value that used in iteration=');

if numberofdisc == 5

J1 =input('Please enter first disc of polar moment of inertia (kgm^2)=');

J2 = input ('Please enter second disc of polar moment of inertia (kgm^2)=');

J3 = input ('Please enter third disc of polar moment of inertia (kgm^2)=');

J4 = input ('Please enter forth disc of polar moment of inertia (kgm^2)=');

J5 = input ('Please enter fifth disc of polar moment of inertia (kgm^2)=');

K1 = input ('Please enter first disc of torsional rigidity (Nm/rad)=');

K2 = input ('Please enter second disc of torsional rigidity (Nm/rad)=');

K3 = input ('Please enter third disc of torsional rigidity (Nm/rad)=');

K4 = input ('Please enter forth disc of torsional rigidity (Nm/rad)=');

for K = Wn:Wnf:Wns

O1 = 1;

O2 = O1 - ((K^2/K1)*(J1*O1));

O3 = (O2)- ((K^2/K2)*((J1*O1)+(J2*O2)));

O4 = (O3)-((K^2/K3)*((J1*O1)+(J2*O2)+(J3*O3)));

O5 = (O4)-((K^2/K4)*((J1*O1)+(J2*O2)+(J3*O3)+ (J4*O4)));

T1 = (J1)*(O1)*(K^2);

T2 = (J2)*(O2)*(K^2);

T3 = (J3)*(O3)*(K^2);

T4 = (J4)*(O4)*(K^2);

T5 = (J5)*(O5)*(K^2);

TT1 = T1;

TT2 = TT1 + T2;

TT3 = TT2 + T3;

TT4 = TT3 + T4;

TT5 = TT4 + T5;

if (x<TT5) && (TT5<y)

fprintf('Result Frequency= %d Radian, Total Torque= %d Newtonmeter\n',K,TT5)

end

end

elseif numberofdisc == 4

J1 =input('Please enter first disc of polar moment of inertia (kgm^2)=');

J2 = input ('Please enter second disc of polar moment of inertia (kgm^2)=');

J3 = input ('Please enter third disc of polar moment of inertia (kgm^2)=');

J4 = input ('Please enter forth disc of polar moment of inertia (kgm^2)=');

K1 = input ('Please enter first disc of torsional rigidity (Nm/rad)=');

K2 = input ('Please enter second disc of torsional rigidity (Nm/rad)=');

K3 = input ('Please enter third disc of torsional rigidity (Nm/rad)=');

for K = Wn:Wnf:Wns

O1 = 1;

O2 = O1 - ((K^2/K1)*(J1*O1));

O3 = (O2)- ((K^2/K2)*((J1*O1)+(J2*O2)));

O4 = (O3)-((K^2/K3)*((J1*O1)+(J2*O2)+(J3*O3)));

T1 = (J1)*(O1)*(K^2);

T2 = (J2)*(O2)*(K^2);

T3 = (J3)*(O3)*(K^2);

T4 = (J4)*(O4)*(K^2);

TT1 = T1;

TT2 = TT1 + T2;

TT3 = TT2 + T3;

TT4 = TT3 + T4;

if (x<TT4) && (TT4<y)

fprintf('Result Frequency= %d Radian, Total Torque= %d Newtonmeter\n',K,TT4)

end

end

elseif numberofdisc == 3

J1 =input('Please enter first disc of polar moment of inertia (kgm^2)=');

J2 = input ('Please enter second disc of polar moment of inertia (kgm^2)=');

J3 = input ('Please enter third disc of polar moment of inertia (kgm^2)=');

K1 = input ('Please enter first disc of torsional rigidity (Nm/rad)=');

K2 = input ('Please enter second disc of torsional rigidity (Nm/rad)=');

for K = Wn:Wnf:Wns

O1 = 1;

O2 = O1 - ((K^2/K1)*(J1*O1));

O3 = (O2)- ((K^2/K2)*((J1*O1)+(J2*O2)));

T1 = (J1)*(O1)*(K^2);

T2 = (J2)*(O2)*(K^2);

T3 = (J3)*(O3)*(K^2);

TT1 = T1;

TT2 = TT1 + T2;

TT3 = TT2 + T3;

if (x<TT3) && (TT3<y)

fprintf('Result Frequency= %d Radian, Total Torque= %d Newtonmeter\n',K,TT3)

end

end

end

The below not code:

ı wanna plot my iteration values, for example x axis is Wn and y axis is TT3 or TT4 or TT5 but when ı write plot (Wn:Wnf:Wns,TT3), it doesn't work. this problem can be caused for too many value such as Wn:Wf:Wns=1:0.01:500.

Thanks for helping

Answer 1

[Ishu]

Hi Ismail,

I understand that you are getting trouble while plotting. But as you can see in your "plot(Wn:Wnf:Wns,TT3)" function, x-axis is a range from 'Wn' to 'Wnf' but y-axis is just a "1*1double". For the "plot()" to perform well you need to provide same size for x-axis and y-axis.

There are two ways to plot a figure in your case:

1. You can use "plot()" while you are iterating.

%This is just an example on how to use plot(), you can make changes in your
%code accordingly
x = linspace(1,10,10); % creates a vector of size 10

for i = x
    y = i^2; % You can replace y values with TT3 TT4 or TT5
    plot(i, y, "o")
    hold on % holds the figure to plot other results
end

2. If you want to use "plot()" only after completing the whole iteration then you can create "TT3", "TT4" and "TT5" as a vector of same size of "K"and then in every iteration store the results in these vectors.

%This is just an example on how to use plot(), you can make changes in your
%code accordingly
x = linspace(1,10,10); %creates a vector of size 10
y = ones(size(x)); % creates a vector of ones with same size of x
hold on
for i = x
    y(i) = i^2; % calculates the values of y
end

plot(x,y, "o");

For more information on "plot()" you can refer to this documentation:

https://www.mathworks.com/help/matlab/ref/plot.html#d124e1143542

Hope it helps!