Phase-field modelling of brittle fracture in thin shell elements based on the MITC4+ approach

We present a phase field based MITC4+ shell element formulation to simulate fracture propagation in thin shell structures. The employed MITC4+ approach renders the element shear- and membrane- locking free, hence providing high-fidelity fracture simulations in planar and curved topologies. To capture the mechanical response under bending-dominated fracture, a crack-driving force description based on the maximum strain energy density through the shell-thickness is considered. Several numerical examples simulating fracture in flat and curved shell structures are presented, and the accuracy of the proposed formulation is examined by comparing the predicted critical fracture loads against analytical estimates