Nicolas Stein

Enhanced XFEM for crack deflection in multi-material joints

In this work, an enhanced eXtended finite element method (XFEM) implementation is outlined. It allows for modeling two-dimensional crack growth including potential crack deflection at significantly tougher constitutents of multi-material continua. At such material interfaces a user-defined crack deflection criterion is utilized that allows for crack deflection parallel to the interface but is also able to model crack growth that again diverges from the interface. The enhanced XFEM implementation is illustrated analyzing crack growth in a plate with two interacting inclusions showing a distinct toughening effect. Moreover, several different adhesive joint design studies are used to validate the model. The results show that the present XFEM implementation allows for an accurate strength and realistic crack pattern prediction in joint designs of complex shape, e.g. with fillets or rounded adherend corners. The given framework is general and could also be applied to the study of fracture processes including crack deflection as e.g. micro-mechanical fracture in fibre-reinforced composites or cracks around inclusions.