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Published on: September 21, 2017
Protection of children in forward-facing child restraint systems during oblique side impact sled tests: Intrusion and
Hans W Hauschild1, John R Humm1, Frank A Pintar1
1a Department of Neurosurgery , Medical College of Wisconsin , Milwaukee , Wisconsin.
Insights
The study found that child restraint system tethers significantly reduce head excursion and injury risk in oblique side impacts, especially with intruded doors. Using a tether is crucial for protecting child occupants in such crash scenarios.
Area of Science:
- Biomechanical Engineering
- Automotive Safety
- Pediatric Injury Prevention
Background:
- Oblique side impacts pose significant risks to child occupants.
- Child restraint systems (CRSs) are critical for mitigating these risks.
- Understanding the influence of specific CRS components and vehicle factors is essential for improving safety.
Purpose of the Study:
- To quantify the kinematics and head injury potential of a center-seated forward-facing child restraint system (FFCRS) in oblique impacts.
- To evaluate the impact of a tether and an intruded door on head kinematics and injury metrics.
- To explore methods for enhancing head protection for child occupants in side-impact crashes.
Main Methods:
- Conducted nine lateral oblique sled tests using a convertible FFCRS secured in the center seating position of a small SUV.
- Simulated oblique lateral acceleration using a 35 km/h delta-V FMVSS 213 pulse with vehicle seats angled at 60° and 80°.
- Incorporated a simulated intruded door structure and tested with and without the FFCRS tether attached.
Main Results:
- Without a tether, all tests resulted in head contact with the simulated door; tether use reduced head contact instances.
- Median Head Injury Criterion (HIC) 15 values were significantly lower with a tether (332) compared to without (589).
- Tethered CRSs exhibited less lateral head excursion (median 400 mm) than untethered systems (median 442 mm).
Conclusions:
- Tethers play a vital role in controlling head excursion and reducing head injury potential for center- or far-side-seated child occupants in oblique side impacts with intruded doors.
- The findings suggest potential improvements through alternative CRS attachment methods or enhanced vehicle side structure protection.
- Further research into CRS attachment and vehicle side protection is warranted to optimize child head kinematics and safety in oblique side impacts.
Objective:
Testing was conducted to quantify the kinematics, potential for head impact, and influence on head injury metrics for a center-seated Q3s in a forward-facing child restraint system (FFCRS) in oblique impacts. The influences of a tether and intruded door on these measures were explored.
Methods:
Nine lateral oblique sled tests were conducted on a convertible forward-facing child restraint seat (FFCRS). The FFCRSs were secured to a bench seat from a popular production small SUV at the center seating position utilizing the lower anchor and tether for children (LATCH). The vehicle seat was fixed on the sled carriage at 60° and 80° from full frontal (30° and 10° forward rotation from pure lateral) providing an oblique lateral acceleration to the Q3s and FFCRS. A structure simulating an intruded door was mounted to the near (left) side of vehicle seat. The sled input acceleration was the proposed FMVSS 213 lateral pulse scaled to a 35 km/h delta-V. Tests were conducted with and without the tether attached to the FFCRS.
Results:
Results indicate the influence of the tether on kinematics and injury measures in oblique side impact crashes for a center- or far-side-seated child occupant. All tests without a tether resulted in head contact with the simulated door, and 2 tests at the less oblique angle (80°) with a tether also resulted in head contact. No head-to-door contact was observed in 2 tests utilizing a tether. High-speed video analysis showed that the head moved beyond the CRS head side wings and made contact with the simulated intruded door. Head injury criterion (HIC) 15 median values were 589 without the tether vs. 332 with the tether attached. Tests utilizing a tether had less lateral head excursion than tests without a tether (median 400 vs. 442 mm).
Conclusion:
These tests demonstrate the important role of the tether in controlling head excursion for center- or far-side-seated child occupants in oblique side impact crashes and limiting the head injury potential with an intruded door. The tether may not influence the kinematics of a near-side-seated occupant as strongly where the vehicle door or side structure interacts with the CRS and influences its motion. The results indicate that there may be an opportunity to improve child head kinematics and head protection in oblique side impacts through different CRS attachment methods and/or alternative vehicle side structure protection or padding.
