Running a while loop for an array

I am trying to run the following length of code through a while loop for different t values checking for the t value which meets both the outlined conditions of the while loop. Any advice on getting it to work?

 if true
    % code
  end
unity = 2;    
t = 0.001:0.001:1;
    while i < length(t+1)

    while (unity(i) > 1) && (unity2 > 1)
    Area = pi.*(D.^2-(D-2.*t).^2)./4;
    P=G./Area;
    [Fa,Fe] = Buckling(D,L,Fy,t,E,k);
    [Fb] = Bending(D,Fy,t,E);

    unity = P./Fa+(Cm.*sqrt(MIP.^2+MOP.^2))./((1-(P./Fe)).*Fb);
    unity2 = P./(0.6.*Fy)+(sqrt(MIP.^2+MOP.^2))./Fb;

    end
    i = i+1;
    end

[Jan]

Hard to answer, because it is not clear what the code should do. If all we see is the failing code, we cannot invent its purpose to fix it.

There are 2 while loops. It is not clear, where you try to check the values of t.

Answer 1

[Jan]

while i < length(t+1)

I guess you mean:

while i < length(t) + 1

This fails, because i is undefined before the loop. Use a for loop instead.

while (unity(i) > 1) && (unity2 > 1)

This fails for undefined variables unity and unity2 also. Define them at first. Is unity a vector or scalar? It is not clear, why you write unity(i) at this line.

Try to fix these points and post the improved code again. Then add clear explanations of the purpose. Otherwise fixing mean guessing.