Seatback Strength and its Effect on In Position and Out of Position ATD Loading in High-Speed Rear Impact Sled Tests
2022-01-1038
03/29/2022
- Event
- Content
- Vehicle rear structure stiffness has increased as a result of the requirements in the FMVSS 301R, which has also corresponded to an increase in front-row seat strength. This study evaluates the structural behavior and occupant response associated with production-level seats equipped with body-mounted D-rings, and very stiff all-belt-to-seat (ABTS) in a group of 12 deceleration sled tests. A double-haversine approximately 100-msec duration pulse was used for all tests, with peak accelerations of approximately 19 g for the 40 km/h (25 mph) tests and peak accelerations of 28 g for the 56 km/h (35 mph) test. This pulse was designed to represent a severe rear impact crash involving modern vehicles. The tests compared occupant responses and resulting structural deformation of an original equipment manufacturer (OEM) production-level driver seat from a pickup and a very stiff modified ABTS. Both seating systems were equipped with dual recliners. Various combinations of tests evaluated the effects of a rear-end impact principal direction of force (PDOF, 5:30 or 6:00), occupant pre-impact seated position (in-position or out-of-position), latch plate design (single-slotted sliding latch plate or dynamic locking latch plate), and pretensioner deployment strategies (none, anchor, and retractor for the production-level seat and buckle for the modified ABTS seat). The OEM seats showed seatback deformation patterns that were indicative of the load path from occupant engagement and were influenced by a number of test-specific factors. The very stiff ABTS seats did not demonstrate appreciable residual seatback deformation. The out-of-position (OOP) anthropomorphic test devices (ATDs) experienced elevated upper neck tension force, extension moment, and neck injury criteria (Nij) compared to the in-position (IP) ATDs in both the production-level and very stiff seats. None of the upper neck metrics exceeded the injury assessment reference values (IARVs) for ATDs in the OEM seats, regardless of the ATD pre-impact posture (IP or OOP). Dynamic test data show that the yielding seat attenuated both the chest accelerations and head/neck injury metrics, whereas the non-yielding seatback in the stiff ABTS seat enhanced upper neck injury potential by rapidly decelerating the ATD torso, particularly for the OOP ATD.
- Citation
- Croteau, J., Toney-Bolger, M., Isaacs, J., Shurtz, B. et al., "Seatback Strength and its Effect on In Position and Out of Position ATD Loading in High-Speed Rear Impact Sled Tests ," SAE Technical Paper 2022-01-1038, 2022, .