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We consider a monolithic phase-field description for fractures in nearly incompressible materials, i.e., carbon black filled ethylene propylene diene monomer rubber (EPDM). A quasi-static phasefield fracture problem is formulated in mixed form based on three different energy functionals (AT2,

AT1 and Wu’s model) combined with two different stress splitting approaches (according to Miehe and

Amor). It leads to six different phase-field fracture formulations in mixed form. The coupled variational

inequality systems are solved in a quasi-monolithic manner with the help of a primal-dual active set

method handling the inequality constraint. Further, adaptive mesh refinement is used to get a sharper

crack zone. Numerical results based on the six different problem setups are validated on crack propagation experiments of punctured EPDM strips with five different test configurations. As a quantity of

interest, the crack paths of experiments and numerical computations are discussed.

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