MATLAB: Greetings, and warn wishes for the new year. I need help in plotting a graph of a equation defined by 3 variables. two of them are lengths and the third one is the angle. So i want to have the values plotted for all different angles.

Question

Here's code i wrote. it runs without any error but i dont see any line plot in the figure. As the equation is a sine function i want to get a plot of sine wave.

With the below codes i get the value of T in each degree from 0 to 360 at unit interval. And i also need to get the average of these values.

Can you please help me this?

I hope i was able to present my question in a understandable way.

i am happy to further clarify.

sdad
hnb
clc; clear all; close all;
l = 0.1; % length of connecting rod
r= 0.05;  % radius of crank arm
P = 500000; %pressure of the system in pascals 
d= 0.05; % diameter of cylinder
A = (pi*d^2)/4; % area of the cylinder
F=P*A;
for B = 0:10:360 %angle    
    
    f=F/(l*(sqrt(1-(r^2/l^2)*(sin(B))^2)));
    T = (f*r/l)*(sin(B))*(r*cos(B)+l*sqrt(1-(r^2/l^2)*(sin(B))^2)) % equation
    plot (B,T ); hold on
    
end
xlabel("Angle (degrees))")
ylabel("Torque (Nm)")
grid on

Answer 1

You don't need a loop at all :

clc; clear all; close all;
l = 0.1; % length of connecting rod
r= 0.05;  % radius of crank arm
P = 500000; %pressure of the system in pascals 
d= 0.05; % diameter of cylinder
A = (pi*d^2)/4; % area of the cylinder
F=P*A;
B = 0:10:360 %angle    
f=F./(l.*(sqrt(1-(r.^2./l.^2).*(sin(B)).^2)));
T = (f.*r./l).*(sin(B)).*(r*cos(B)+l.*sqrt(1-(r.^2./l.^2).*(sin(B)).^2)) % equation
xx=linspace(B(1),B(end),1000);
yy=interp1(B,T,xx,'pchip');  % if you need a smooth curve
plot(B,T,'o',xx,yy,'r'); 
xlabel("Angle (degrees)")
ylabel("Torque (Nm)")
grid on