Hi Akshay,
To plot a graph between kq and b while also ensuring the condition Y1 < Y is satisfied, you can use a loop to evaluate the expressions for a range of b values and then plot the corresponding kq values that satisfy the condition. Here is an example code that demonstrates this approach:
(Note that you need to define the variable alphacm and you didn't provide the equation for it in your code snippet, so you may need to add that in if you haven't already. Also note that the range of b values in the example code is just an arbitrary range - you may need to adjust it based on the specific problem you are trying to solve.)
H = 4;
gama = 18.4;
q = 10;
const = pi/180;
phi = 30*const;
delta = 0*phi;
psi = 0;
f = phi+delta;
g = phi-psi;
h = psi+delta;
a = 0.5;
% Create a range of b values
b_values = 0.1:0.1:3;
% Evaluate kq for each b value and plot the ones that satisfy Y1 < Y
kq_values = zeros(size(b_values));
for i = 1:length(b_values)
% Compute q'
qb = q*b_values(i)/(b_values(i)+(2*a));
% Compute nq
nq = 2*qb*(H-a)/(gama*(H^2));
% Compute kq
r = (b_values(i)/(H-a))*tan(alphacm);
kg = ((tan(alphacm-phi)+tan(psi))*cos(alphacm-phi))/(tan(alphacm)*(cos(alphacm-phi-delta)));
kq = r*kg;
% Check if Y1 < Y
Y = H/tan(alphacm);
Y1 = a+b_values(i);
if Y1 < Y
kq_values(i) = kq;
end
end
% Plot kq vs. b for the values that satisfy Y1 < Y
plot(b_values(kq_values~=0), kq_values(kq_values~=0))
xlabel('b')
ylabel('kq')
