This paper describes how a finite element model of a 7-month pregnant uterus was created and integrated into a multi-body human model. The uterine model contains 11,632 elements and 16,335 nodes. The pregnant model was validated using known abdominal response corridors. Unrestrained, 3-pt belt, and 3-pt belt plus airbag tests were simulated at speeds ranging from 13 kph to 55 kph. Peak uterine strain was found to be a good predictor of fetal outcome (R(2) = 0.85). The strain in the uterine wall exceeded 60%, which was sufficient to cause abruption, in simulations of no restraint at 35 kph and 3-pt belt tests at 45kph and 55 kph. These tests represent a greater than 75% risk of adverse fetal outcome. For matched tests at 35 kph, strains of 60.8% for the unrestrained occupant, 52.6% strain for the 3-pt seatbelt and airbag combination were recorded. The model proved successful at predicting risk of fetal demise and verified the experimental findings by noting the importance of proper restraint use for the pregnant occupant.
Abstract