//Defines the equations for the flexural buckling of members without slender elements (AISC 360 E3)
//After running the script, the elastic buckling stress, nominal stress, and nominal compressive 
//strength can be computed for a given effective length 

//Elastic Buckling Stress
double Fe(double lc)
{
    return Math.PI * Math.PI * GetSectionProperty("E") / Math.Pow(lc / GetSectionProperty("r2"), 2);
}

//Nominal Stress
double Fn(double lc)
{
    var fy = GetSectionProperty("Fy");
    var fe = Fe(lc);
    if(fy/fe <= 2.25)
    {
        return Math.Pow(0.658, fy/fe) * fy;
    }
    return 0.877 * fe;
}

//Nominal Compressive Strength 
double Pn(double lc) => Fn(lc) * GetSectionProperty("Area");