ABSTRACT Composite Overwrapped Pressure Vessels (COPVs) are widely used in space launch vehicles and the automotive industry. Due to the potential for catastrophic loss caused by failure of COPVs, improved understanding of its mechanical and damage growth behavior is necessary to ensure its safe operation. In this paper, we described a developed mesoscopic model with the capability of modeling tows/yarns with inserted, in-ply interface elements and interface layers as resin rich zones. Furthermore, the model realizes 1) arbitrary winding angle build-up of overwrap plies, 2) controllable detailed dimensions, and 3) user defined material behavior for all regions. These features are critical for potential studies of in-situ and parametric overwrap failure in COPVs. In the present work, stress profiles and progressive failure around a single tow break are shown by case studies involving various interface and damage evolution properties. The investigation indicates that the strength and damage evolution law of interface elements both have direct effect on the stress concentration factors and damage evolution around a tow break/fracture. Resulting physical phenomena and stress overload profile are discussed as well.