Crash Test Facility Upgrade for NHTSA Oblique Test with Residual Energy Control and Advanced Barrier Force Measurement 2018-01-1056

The objective of this study was to design and implement laboratory countermeasures for kinetic energy management in the NHTSA 90 kph oblique front impact crash test. In addition, an advanced force distribution analysis method was developed by upgrading the oblique moving deformable barrier (OMDB). The residual kinetic energy of the oblique test can be challenging to safely control, especially for smaller crash labs. The residual energies can be greater than other front crash modes by more than 50% of the initial energy. Wheel brakes on the OMDB and target vehicle may not be enough to contain the crash. Two tether systems were designed: one between the OMDB and towing cable and the other between the test vehicle and ground. Both tether systems use a hydraulic brake caliper and rotor to provide controlled payout and energy absorption. Current OMDB has basic sensing capability to measure kinematics but it has a limited ability to study dynamic force distributions. The OMDB was upgraded by covering the entire front face with custom designed load cell array without altering the original mass distribution.

The tether system and load cell array were validated with a compact passenger car to represent a worst-case scenario. The residual kinetic energy after separation of the OMDB and vehicle was 585 kJ (75% of total initial energy) which includes 397 kJ for the OMDB and 187 kJ for the vehicle. The OMDB tether absorbed 176 kJ (44%) of the residual energy and the vehicle tether absorbed 34 kJ (18%). The OMDB face load cell data showed a total peak load of 350 kN at 36 ms. The test with a compact passenger vehicle demonstrated that the implemented countermeasures were safe and efficient. The added load cells improved the analysis capability of the OMDB by recording dynamic loading time histories during the entire crash event.