Undefined Function or Variable

Hi, can anyone see why I am getting the error message '''Undefined Function or Variable R'' . As far as I understand I had already defined R...

Many thanks!

gamma = 15; % Unit weight, Kg/m^3
colRadius = 0.17; %  Column Radiu, m 
theta = 1*(180/pi); % Angle of failure to the horizaontal surface 
phi = 15*(180/pi); % Angle of internal friction

depth = zeros(14,2); % Depth, m
for i = 1:19
    depth(i,1)=i;
    depth(i,2)=2.25+(0.5*i);
    p(i,1) = gamma*depth(i,2)*((depth(i,2)/colRadius)^2+(3*(depth(i,2)/colRadius)*tan(theta))+(3*tan(theta)*tan(theta)))/(3*tan(theta)*tan(theta))*(1+(2*(1-sin(phi)*cos((180*(180/pi))-(theta+phi))))/(cos(phi*cos(theta))));
end

gamma = 15; % Unit weight, Kg/m^3
colRadius = 0.17; %  Column Radiu, m 
theta = 1*(180/pi); % Angle of failure to the horizaontal surface 
phi = 15*(180/pi); % Angle of internal friction
E = 2 ; % Modulus of soil deformation, Kpa
n = 1; % Exponant in empirical equation
p = (200); % Applied pressure at the grout soil interface, kPa
c = 5% cohesion 
Ri = 0.06; % Drill radius
Ir = 5 % Rigidity index of soil 
v = 2 % Poisson's ratio
q = 2 % Initial Isotropic Ground Stress

a1 = ((1/Ir)-1+1*(-(1+v/2*E))*(4*sin(p)/3-sin(phi))*(q+c*cot(phi)))^3;

a2 = c*cot(phi);

a3 = (3*(1+sin(phi))/(3-sin(phi))*(q+c*cot(phi)));

a4 = (3*(1-sin(phi)))/(4*sin(phi));

a5 = (1/Ir);

try

   R = (Ri/(a1(p+a2/a3)^a4)+(a3/p+a2)^a4)-a5^(1/3);
   
catch
end

figure;
hold on
plot(p,R)
xlabel('Injection Pressure (KPa)');
ylabel('Bulb Radius (kPa)');

Answer 1

[Dimitris Kalogiros]

I think there is a typo at the formula that calculates R :

Something is missing there. Maybe a + or * mark

By the way, calculation of R gives an error. Since you have enclose it inside "try-catch" , there is no variable R when the script is trying to plot it.

Correct the typo, remove try-catch and try again....

[James Leak]

Thank you, I had not noticed that I had missed a *.

Kind regards,

James

Answer 2

[meghannmarie]

You are not setting R becuase you have it in a try catch block and it is throwing an error. That is because you are tryind to index a1, but are you really wanting to multiply a1?

Should:

R = (Ri/(al(p+a2/a3)^a4)+(a3/p+a2)^a4)-a5^(1/3)

actually be:

R = (Ri/(al*(p+a2/a3)^a4)+(a3/p+a2)^a4)-a5^1/3

[Steven Lord]

meghanmarie had flagged this answer:

Flagged by meghannmarie about 1 hour ago.

It marked my answer as spam and it is not

I had marked the answer not spam and I am removing the flag.

[James Leak]

Thank you very much! this sorted it out perfectly.

Kind regards,

James