Research On The Safety Of Pregnant Occupants In Frontal Impacts

While the automobile brings great convenience to human, it also causes large numbers of traffic accidents which result in many personnel casualties and economic loss. Since entering the 21th century, people pay more and more attention to the vehicle safety. All of these impel the governments and vehicle manufactures all around the world to invest much manpower and wealth resources in improving vehicle safety. As a result, the improvement of passive protection of common occupants and children is obvious, but the research of pregnant occupants is just on the first step.Based on investigating a large amount of literatures, the abdominal anatomy, the method to build a pregnant occupant model and how to protect the pregnant occupants were investigated in-depth. A 30-week pregnant 3-D uterus model was constructed in the software UG, and the model was meshed by using the software HyperMesh. The FE model of the uterus was inserted into the 5th percentile female facet occupant model to build the pregnant occupant model, and the two models were coupled together using the software MADYMO R6.2.1. Then the reliability and stability of pregnant occupant model were validated via the abdominal response corridors under rigid bar loading and belt loading.The frontal impact model of driver and passenger side were constructed according to a domestic production vehicle. The injuries of the pregnant drivers and passengers during the frontal impacts were compared using the models built before. The researches indicated that, the injury parameters of the pregnant drivers and passengers were close to each other when the impact velocity was lower than 20 km/h. But while the impact velocity was higher than 30 km/h, the peak value of the uterine strain at UPI(Utero-Placental Interface) of the driver was greater, and the injuries parameters of the maternal in driver position were greater than passenger. Aiming at the injury mechanism for pregnant passengers, a new kind of safety belt combined with traditional 3-pnt belt was developed. The results of the simulation indicated that the new safety belt could enwrap the abdomen of the pregnant women, and reduce the uterine strain at UPI which was caused by the inertial of the amniotic fluid and the fetus, meanwhile it would not decrease the protective effects of the traditional 3-pt belt on the maternal. In addition, the best protection can be obtained by using the enwrapping fabric whose prolongation ratio was 14.5%.At last, the new kind of safety belt for pregnant passengers was tailored, and the 5th percentile Hybridâ…¢female dummy was refitted, a series of sled tests were conducted using the new belt and the dummy. The results of the tests indicated that the new safety belt could reduce the displacement of the pregnant women's abdomen.