NUMERICAL SIMULATION AND OCCUPANT INJURY PREDICTION UNDER SIDE IMPACT LOADING USING HUMAN SURROGATE MODEL

Side Impact, after frontal impact is one of the major causes of concern for seated occupants during road accidents. Study of injury to occupants under side impact scenarios is important to design and develop reliable and efficient safety systems that can reduce the effect during crashes. In the present work, a typical side impact scenario is modelled using finite element method and human surrogates. Aluminum plates were modelled that represent a scenario in a side impact road accident where a door may infringe into the occupant seating area. The plates were impacted at a constant velocity of 4.3 m/s along the right side of the 50th Percentile Male LSTC World Side Impact Dummy (WSID) Finite Element Model and the biofidelic response was evaluated. The pelvis and lower extremity plates were offset by 10 cm closer to the subject to simulate a typical geometry of a side door panel during a side impact. The model is validated against experimental data available in the literature by considering the forces on the plates and nodal acceleration response on full body side impact studies using Anthropomorphic Test Devices (ATD) and Post Mortem Human Subjects (PMHS). The severity of injury in this scenario is found to be more than frontal impact since the occupant is struck on the side and is seated in close proximity to the side structures. Also, safety mechanisms in the vehicle like the seat belt may not be effective in negating the injury from a side impact. The simulation results were found to be well within the PMHS response available in the experimental data. The biofidelic response of the FE surrogates was also studied to estimate the severity of the injury based on a set of injury criteria/injury assessment risk curves (IARC) that has been developed for the WSID dummy. The simulation predicted severe pelvic injuries due to the offset of the pelvis plate. Also the pelvic forces obtained on the plates in the simulation were higher than the actual PMHS response. The simulation predicted that there was a 30% risk of thoracic injuries. Injury patterns in side impact scenarios were studied in detail and probabilities based on IARC were estimated to predict injury severity and compared with standard IARV (Injury Assessment Reference Values). The numerical model developed in the present approach can be a valuable tool in assessing the performance of passenger side automotive airbags during its design and initial development phase.