Fundamental differences between fracture behavior in tension and
compression should be taken into account. However, Eq.(3) does not
differentiate
between that behavior.
Already in Amor et al 28 examples of unrealistic
crack patterns under compression have been documented. To prevent such
situations a derived regularized formulation of Eq.(1) has been
suggested in Miehe et al 8,9. The corresponding
approximation takes the form as follows: