Level: Intermediate
Sean Kohles, Owner and Research Professor, Kohles Bioengineering
Rear-end motor vehicle crashes have been strongly associated with occupant cervicocranial biomechanics that lead to neck injury. An analytic mechanics model of occupant head and neck motion was developed associating target vehicle Delta V during rear-end crashes. The inclusion of stochastic mechanical input variables further developed the model beyond the deterministic framework. Specifically, a biomechanical algorithm was constructed with statistical software (JMP Pro 12). This approach applied the randomization functions (e.g., 1+RandomUniform(VehicleSpeed)*19), which generated uniformly random vehicle closing speeds for each stochastic simulation. Additional inclusion of randomized variables such as bullet/target vehicle weights, coefficients of restitution, and neck extension angles also contributed to the stochastic model. The random nature of 1,000 crashes was simulated. An embedded data profiler was created and saved as a hypertext markup language file so that isolated input variables could be individually manipulated, examining variations in the simulation. The model was validated through the direct comparison with 86 published human subject crash tests. Further calculation of applied occupant inertial forces was incorporated into an injury probability model to identify injury causation. The utility of the model allows an investigator to customize some of the basic input crash parameters and explore the resulting influence on injury biomechanics.
