Evaluation of the MADYMO Full FE Human Model in a Rear Impact Simulation of an IndyCar 2006-01-3659
Computer simulation was used as a complement to crash and injury field data analysis and physical sled and barrier tests to investigate and predict the spinal injuries of a rear impact in an IndyCar. The model was expected to relate the spinal loads to the observed injuries, thereby predicting the probability and location of spinal fractures. The final goal is to help reduce the fracture risk by optimizing the seat and restraint system design and the driver's position using computer modeling and sled testing.
MADYMO Full FE Human Body Model (HBM) was selected for use because of its full spinal structural details and its compatibility with the vehicle and restraint system models. However, the IndyCar application imposed unique challenges to the HBM. First, the driver position in a race car is very different from that in a typical passenger car. Second, the crash pulse of an IndyCar is much more severe than that of a typical passenger car crash test such as the New Car Assessment Program (NCAP). Third, the rear impact simulation requires an omni-model, while many HBMs were designed with a focus on frontal impacts.
The most recent version of MADYMO Full FE HBM (version 6.3) has the capability to output force and torque of the spine system. But it lacks the flexibility to be positioned in the IndyCar without significant initial force and torque resulting from the positioning. Also the model often becomes unstable with joint disruptions and misrepresentation of the contacts among the skeleton, internal organs and the skin. Upon further investigation and consultation with the TNO Automotive Safety Solutions (TASS), it was concluded that the FE Human model is not suitable for the current IndyCar severe rear impact applications. The alteration of the HBM would take extensive efforts.
As a result, a less detailed MADYMO facet HBM was used instead. The performance of the facet HBM in the IndyCar application will be reported in later publications.