%Checks the possibility of fully elastic

function [k]=Section2

    %Checks the possibility of fully elastic
    global dflange bf Ec fs Es epcp;
    global d As M;
    %M=Z.Ft
    %Ft=As.Es.eps
    %Fc=0.5.x.b.Ec.epc
    %Ft=Fc
   
    %epc/eps = x / d-x
    %0.5bEcx2 + AsEsx - AsEsd=0

    a=0.5*bf*Ec;
    b=As*Es;
    c=-As*Es*d;

    p=[a b c];
    xm=roots(p); %mm
    x1=xm(1);
    x2=xm(2);

    if (x1>0)
        x=x1;
    else if (x2>0)
            x=x2;
        end
    end

    %Check whether x is within flange
    if (x<dflange)
        %disp('x is in flange')
    else (disp('x is NOT in flange'))
    end

    %Calculate strain in steel and check the failure

    z=d-x/3;
    Ft=M*1000000/z;
    eps=Ft/(As*Es);
    epsp=0.87*fs/Es;

    %Check limiting plastic strain in concrete
    %if epcp>epc fully elastic ok

    epc=eps*x/(d-x);
    %disp (num2str(epc));
    if (epc<epcp)
        %disp ('completely elastic possible');
        if (eps<epsp)
            %disp ('steel is also ok');
        else
            %disp ('Steel fails');
        end
    else
        disp ('go to plastic');
        [epc, x]=Plast2;
    end
    k=epc/(x/1000);
end