Numerical Modelling of Mixed Mode Cohesive Crack Propagation

The influence of shear on the process of cracking in concrete structures is of great practical importance. In the terminology of fracture mechanics, this is called Mode II or Mixed Mode loading. According to the ‘Fictitious Crack Model’,the non-linear crack behavior can be described by means of cohesive forces in the damage zone representing the aggregate interlocking and bridging. Using Finite Element Method (FEM) and inter-element crack propagation, continuous modification of the mesh and nodal renumbering is required. This paper presents a review of some computational results obtained by a program developed by the authors and performing the above mentioned procedure. Quadratic displacement isoparametric elements are used. Strain-softening at the crack surface is included.