I would save them as cell arrays:
anglev = (-45:45:90)*pi/180; % Angle Vector
for k1 = 1:length(anglev)
angle = anglev(k1); % Angle
m = cos(angle);
n = sin(angle);
Stress_matrix_1{k1} =[m^2 n^2 -2*m*n;
n^2 m^2 2*m*n;
m*n -m*n m^2-n^2];
Strain_matrix_1{k1} = [m^2 n^2 -m*n;
n^2 m^2 m*n;
2*m*n -2*m*n m^2-n^2];
Q_bar{k1} = (Stress_matrix_1)*(Q_matrix)*inv(Strain_matrix_1)
end
Also, if you want to use degrees, you can avoid the conversion to radians in your code, and use the cosd and sind functions. In my experience, they’re more accurate for degree arguments than doing the conversion in your code.
