Bug: eps_cu1 called with fcm instead of fck in _concreteEC2_2004.py

[elliotmelcer]

Inside of _concreteEC2_2004.py eps_cu1 is calculated by ec2_2004.eps_cu1(self.fcm), but the function eps_cu1() within _concrete_material_properties.py expects fck as an input, NOT fcm.

_concreteEC2_2004.py:

@property
    def eps_cu1(self) -> float:
        """Returns the strain at concrete failure of concrete.

        Returns:
            float: The maximum strength at failure of concrete.

        Note:
            The returned value is derived from fcm if eps_cu1 is not manually
            provided when initializing the object.
        """
        if self._eps_cu1 is None:
            return ec2_2004.eps_cu1(self.fcm)
        return self._eps_cu1

_concrete_material_properties.py:

def eps_cu1(fck: float) -> float:
    """The ultimate strain for the Sargin constitutive law.

    EN 1992-1-1:2004, Table 3.1.

    Args:
        fck (float): The characteristic compressive strength of concrete in
            MPa.

    Returns:
        float: The ultimate strain, absolute value, no unit.
    """
    fck = abs(fck)
    return (
        3.5 / 1000
        if fck < 50
        else (2.8 + 27 * ((98 - fcm(fck)) / 100) ** 4) / 1000
    )

[mortenengen]

Thanks for reporting this, @elliotmelcer! I have submitted a fix in #307 😃 If accepted, you can expect it to be included in our next release in early January.