Simulating Occupant Response to Low Speed, Automotive Rear-End Collisions

This paper outlines the modeling and analysis of an occupant’s response to a low speed, in-line, rear end collision. The response of the occupant was modeled using two methods; MATLAB was used to model the equations of motion of the occupant’s head, neck and spine and ANSYS Workbench was used to perform a structural analysis of the occupant’s spine and head. The occupant was assumed to be an average sized male, with a spine length of about 30”. The occupant was also assumed to be unaware of the impact, therefore not bracing themselves against the impact. Both of the vehicles were assumed to be 2000 kg. The leading (target) vehicle is stopped producing a velocity of 0 km/h, and the trailing (bullet) vehicle is going 16.1 km/h (10mph) producing an acceleration on impact of 22.35 m/s2. Both the MATLAB model and ANSYS model assumed that the occupant was not wearing a seat belt. The ANSYS simulation produced an acceleration of the head of 9.40 g’s, while the MATLAB model produced 5.10 g’s of acceleration at the head. These values were compared to literature of experimental crash tests. The results obtained from the two models were compared to one another as well as literature values from multiple sources to validate the results obtained. This report will outline the formulation of the two models, the results obtained from the two models, a comparison between the models, and a comparison to literature results for experimental test data.