Textile composites exhibit multiple potential failure modes in structural or impact applications. Accurate modeling of these modes enables effective material design and structural design through multi-scale modeling and design from the micromechanical to application level. In dynamic impact events, interface failure between the fiber tow and interstitial matrix represents a common failure mode not explicitly captured in many models. This phenomenon is seen to be driven by rate-dependent interface fracture properties with both rate and fracture mode sensitivity. This paper focuses on development of a model for interface failure to be employed within a textile micromechanics model in later works. Simulation has enabled insight into the dynamic in-situ stress state and crack growth under impact for property determination and test specimen evaluation. A rate-dependent cohesive failure criterion has been successfully employed and agrees closely with published experimental results at multiple strain rates. Both rate and mode-mixity effects on failure have been successfully included.