Chest Injuries in Heavy Vehicle Frontal Collisions - Evaluation and Adaptation of the Hybrid III Dummy Instrumentation and Injury Reference Values by Means of Human Body Modeling

Licentiate thesis, 2009

The safety of passenger cars has been significantly improved during the last decades. Similar improvements are not as apparent in heavy vehicles and one of the reasons is believed to be deficiencies in heavy vehicle crash testing and the tools used to evaluate the biomechanical responses. The most commonly used dummy for frontal vehicular crash testing is the Hybrid III. This dummy was mainly intended for testing safety in passenger cars and is as such not appropriately evaluated for use in heavy vehicle driver environments. This research was initiated to evaluate the Hybrid III and its instrumentation for use in heavy vehicle frontal crash testing. The lack of appropriate biomechanical evaluation data lead to a new approach to Hybrid III chest performance evaluation. Finite element modeling was used as an alternative tool. Human body models and Hybrid III models were utilized and the results were compared. It became evident that the contact between the steering wheel rim and the driver’s chest was a critical load situation. A representative load case for heavy vehicle frontal collisions was identified. The occupant models were then evaluated using the best available validation setup. The THUMS proved to be the best available human body substitute in this context. The THUMS was thus used, coupled with the better of the two available Hybrid III models. A suitable Hybrid III chest deflection instrumentation has been identified and a transfer function between the Hybrid III chest response, during steering wheel rim contact, and established chest injury criteria were developed.