Occupant models require a means to translate between model measurements and injury risk. Rib fracture injury risk functions have been developed for ATDs and some human body finite element models(HBMs). This study develops frontal-impact rib fracture injury risk functions (IRFs) for use with Simcenter Madymo’s Active Human Model (AHM). One hundred and seventy simulations were performed in 13 load cases, with each simulation matched to a specific past PMHS test. Injury risk functions were developed for predicting the risk of 3+ rib fractures, and 7+ rib fractures. The maximum chest deflection from the four measurement sites in the AHM was selected as the final predictor, due to its predictive fit and its low sensitivity to changes in loading location. This process may be repeated to refit the injury risk function when future updates are made to the model, allowing distribution of the injury risk function for use with the specific model for which it was tuned. These results demonstrate that it is possible to fit model-specific injury risk functions for human body models that use different modeling methodologies, facilitating flexibility in choice of human body model to fit the needs of various applications.