he problem of optimizing composite effectiveness has been studied for as long as these materials have existed. One way this effectiveness is characterized is by the shear strength of the bond between fiber and resin, called interfacial shear strength (IFSS). If the composite IFSS is weak, then little load is transferred from the compliant resin to the stiff and strong fiber thereby reducing composite effectiveness. Simulations were conducted to model this property of a composite material. Two different models were used and combined, one at the microscale representing an experiment and one at the nanoscale to represent interactions at the interface. The models were calibrated and compared against experimental data for the single fiber fragmentation test (SFFT) found in the literature. The microscale model showed good agreement with experimental data while the nanoscale model indicated that texturing of the fiber surface can have a large influence on composite IFSS.