@classmethod
def from_nominal(cls, nominal_strength=None):
    """
        Alternative constructor creating a steel material from a given nominal strength.

        Parameters
        ----------

        nominal_strength : str
            Steel quality, given in the form of e.g. "S355"

        """
    if nominal_strength is None:
        f_yield = 235.0
    else:
        f_yield = float(nominal_strength.replace('S', ''))
    plasticity = cls.plastic_table(nominal=nominal_strength)
    return cls(210000.0, 0.3, f_yield, plasticity=plasticity)
