Prediction of the Segmental Pelvic Ring Fractures Under Impact Loadings During Car Crash

The Pelvis is the most susceptible part of the body to damage during car accidents and is characterized by the highest mortality rate, especially in the case of multiple fractures. The mechanism of these fractures remains unclear and this makes the development of effective crash protection more difficult. A geometric model of the lumbo-pelvic-hip complex (LPHC) including elements of skeletal, muscular and ligament structure stabilizing the pelvis was elaborated on the computed tomography images of a 25-year-old patient. The influence of pelvic boundary conditions on the type of injuries was subjected to analysis using the Finite Element Method (FEM). The cases of a model anchorage dependent on the position of the passenger’s body in the vehicle, where the impact of interior vehicle elements, such as seat belts or a car seat, were taken into account. A fracture threshold was established by applying lateral loads from 0 to 10 kN to a greater trochanter of the femoral bone in each of a five cases of boundary conditions reflecting the influence of different car parts on a passenger’s body. The magnitude of the contact force between the body and the vehicle parts during a side collision against the driver’s door were determined using the elaborated model. Furthermore, a pelvis lateral collision theory model was built and validated with the use of clinical data. The obtained results can provide an estimate for a threshold of the initial failure in the pelvis bone due to an impact compression transmitted through an overlying tissue. Therefore, it was assumed that the properties of the fractured structure are similar to the cancellous bone.