The National Highway Traffic Safety Administration (NHTSA) as an update to New Car Assessment Program (NCAP) for the model year 2020 vehicles will be introducing Oblique Impact Test procedure with a Research Moving Deformable Barrier (RMDB) and Test device for Human Occupant Restraints (THOR) as new Anthropomorphic Test Device (ATD) in both driver and passenger seat. During the oblique impact test, the vehicle translates and rotates in XY plane and as a result dummy moves in oblique direction inside the vehicle making a partial contact with the deployed airbag restraints. The NCAP update will also introduce the new head injury criterion for brain rotation measurement called Brain Injury Criterion (BrIC). Given the dynamics of oblique impact test, partial dummy interaction with restraints, and new head injury criterion BrIC it has become very critical to understand the vehicle and dummy motion in the three dimensional space during the test for the development of restraints system.

The objective of this study to generate 3-D translational and rotational motion of vehicle and dummy using “Rigid Body Prescribed Motion” numerical scheme of LS-DYNA solver by processing sets of test data output from accelerometers and Angular Rate Sensors (ARS) in vehicle and ATD.

A numerical model consisting of finite element vehicle model and finite element head model of Test device for Human Occupant Restraints (THOR) was developed. The LS-DYNA numerical model generates a global reference frame data format by transforming output from accelerometer and ARS in vehicle and ATD. The acceleration and rotational output data from the numerical model was co-related with acceleration and rotational from the NHTSA vehicle test RC5370 and used for model validation purpose. The results from video film analysis of vehicle motion in NHTSA test compared with generated translational and rotational motion from the numerical model as a final confirmation.

The oblique motion angle of dummy in vehicle during the oblique impact test is critical in determination of setup for the oblique sled testing. The output from the numerical model can be useful to determine the appropriate angle for the oblique sled testing. This numerical model can also be useful for the development of optimal restraints necessary in various crash impact modes.