clc
clear all
clear Figure1
nd=1.5;
d=8;
F=250;
Sut=2211/d^0.145;
Sr=0.45*Sut;
Se=0.5*Sr*(1-(0.45/2)^2)^(-1);
c=linspace(-15,15,1000);
O=F*((4*c.^2-c-1)*16./(4*(c-1)*3.14*d^2)+4/(3.14*d^2));
Q=nd*O/Se+(nd*O/Sut).^2-1;
%Q=(nd*F*4/(3.14*Sut*d^2))^2*((4*c.^2-1)./(c-1)).^2+nd*F*4/(3.14*Se*d^2)*((4*c.^2-1)./(c-1))-1;

Qmin=min(abs(transpose(Q)));
for i=1:1000
    if Q(i)==Qmin
        C=c(i);
        fprintf('Qmin= %g C=%g\n',Qmin,C);
    end
end

plot(c,Q);
hold on;
z=linspace(0,0,1000);
plot(c,z,'r');
axis([0 15 -6 5]);

d=d/1000;
Lmin=0.377;
Lmax=0.89;
Ymax=Lmax-Lmin;
G=80*10^9;
E=200*10^9;
D=C*d;
k=500/Ymax;
Na=G*d^4/(8*k*D^3);
Nb=Na-G/E;
L0=(2*C-1+Nb)*d;
Li=Lmin-L0;
Fi=Li*k;

fprintf('d=%g 4<C=%g<12 D=%g 3<Na=%g<15 L0=%g \nSut=%g Sr=%g Se=%g k=%g Li=%g Fi=%g',d*1000,C,D*1000,Na,L0,Sut,Sr,Se,k,Li,Fi);