Interface element including point‐to‐surface constraints for three‐dimensional problems with damage propagation

An interface finite element for three‐dimensional problems based on the penalty method is presented. The proposed element can model joints/interfaces between solid finite elements and also includes the propagation of damage in pure mode I, pure mode II and mixed mode considering a softening relationship between the stresses and relative displacements. Two different contact conditions are considered: point‐to‐point constraint for closed points (not satisfying the failure criterion) and point‐to‐surface constraint for opened points. The performance of the element is tested under mode I, mode II and mixed mode loading conditions.