using a specific additive decomposition\(\psi_{e}={\psi_{e}}^{+}+{\psi_{e}}^{-}\)of the elastic energy density \(\psi_{e}\), in contrast to Eq.(6), the degradation of only the positive energy part is allowed herein, whereas the negative part remains undegraded. The \({\psi_{e}}^{+}\) represents tensile contributions and \({\psi_{e}}^{-}\) represents compressive contributions to the stored elastic strain energy. This modification provides a mechanism for distinguishing states of strain under which cracks will growth. In Contrafatto29 the trace of the elastic strain tensor was used as separating interface. This approach has also been followed by Faria30 and Ambati31. In such a way the elastic energy takes different forms according to the sign of the elastic strain tensor.28