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The cohesive model for crack propagation analyses is incorporated into finite elementprograms by interface elements, which simulate the material separation. A drawback ofthese elements for the prediction of crack paths is that they are generated prior to thesimulation and the number of possible directions for crack extension is limited. If thereare only a few alternatives for the crack to extend, however, i.e. in bifurcationproblems, interface elements can be profitably used for the numerical prediction ofcrack paths. Examples for this kind of problems will be given on both, the macroscopicand the microscopic scale. The former is the simulation of a stiffened cylindrical shellunder internal pressure, where a skin crack may penetrate the rib or deviate. The latteris a unit-cell calculation for a fibre-reinforced material, where the fibre may debond orbreak.