public double MaxRebarStrain(List <double> ReinforcingStrains)
        {
            List <double> diList = ReinforcingBars.Select(x => x.di).ToList();
            int           i      = diList.IndexOf(diList.Max());

            return(Math.Abs(ReinforcingStrains[i]));
        }
 public double MinRebarDi()
 {
     return(ReinforcingBars.Select(x => x.di).Min());
 }