On a case of crack path bifurcation in cohesive materials

Experimental, theoretical and numerical investigations show that crack kinking and crack branching can be observed and simulated in brittle solids and in the fast dynamical propagation of quasi-brittle fractures. The present study shows that kinking and branching may also occur in the quasi-static regime when an isotrophic or equi-biaxial tensile state of stress arises at the tip of a cohesive crack, and may represent alternative itineraries (i.e. path bifurcation) of the fracture process. Specific reference is made to the common but meaningful case of the three-point-bending test. Various numerical techniques apt to capture the above occurrence are comparatively presented, and the in influence of path bifurcation on the overall behaviour of the specimen is discussed.