Oving4

T_0 = -20; %deg C
T_end = 60;%deg C
T = linspace(T_0,T_end,500);
A = 350; %mm^2
E = 80e9; % Pa
delta = 2.2; %mm
L = 3000; %mm
alpha_1 = 18e-6;

F_1 = zeros(1,length(T));

for i = 1:length(T)
        F_1(i) = A * E * (alpha_1 * abs(T(i)-T_0) * L - 2.2)/(L + alpha_1 * abs(T(i)-T_0) * L);
end

F_2 = zeros(1,length(T));
alpha_2 = zeros(1,length(T));

for i = 1:length(T)
    alpha_2(i) = (18-0.0002 * T(i)^2 + 0.0001 * T(i)^3) * 1e-6;
    F_2(i) = A * E * (alpha_2(i) * abs(T(i)-T_0) * L - 2.2)/(L + alpha_2(i) * abs(T(i)-T_0) * L);
end

F_1(F_1 < 0) = 0;
F_2(F_2 < 0) = 0;

hold on
plot(T, F_1, '-r')
plot(T, F_2, '-g')