Sheet metals like Al, Ti and Mg used in aerospace and automotive industries have high strength to weight ratio but low ductility. These materials develop plastic anisotropy in metal-forming operations during their manufacturing process. Plastic anisotropy and damage due to micro-void growth must be considered in the constitutive modeling of materials to predict failure accurately. Several models have been proposed to study failure in anisotropic materials at high triaxiality. However, an accurate model that considers non-proportional loading occurring in multiaxial operations and shear-dominated loading occurring in low triaxiality conditions is not developed. The proposed failure model predicts failure for anisotropic materials for various loading conditions, including non-proportional and low triaxiality loading conditions. The proposed model can be a crucial tool to mitigate experimental efforts to predict failure of sheet metals during manufacturing and service conditions.