public static double TorsionalConstant(this BoxProfile profile)
{
if (profile.IsNull())
{
return(0);
}
double t = profile.Thickness;
double width = profile.Width;
double height = profile.Height;
double rc = (profile.OuterRadius + profile.InnerRadius) / 2;
double h = 2 * ((width - t) + (height - t)) - 2 * rc * (4 - Math.PI);
double ah = (width - t) * (height - t) - Math.Pow(rc, 2) * (4 - Math.PI);
double k = 2 * ah * t / h;
return(Math.Pow(t, 3) * h / 3 + 2 * k * ah);
}
public static double WarpingConstant(this BoxProfile profile)
{
return(profile.IsNull() ? 0 : 0);
}