Dynamic Comparison of Pediatric and the Small Female ATDs to Size-matched Pediatric Volunteers (Multiple Year Project)

Principal InvestigatorThomas SeacristMBE, The Children’s Hospital of Philadelphia

 

Below is an executive summary of this line of research. Please note that each summary describes results and interpretation that may not be final. Final interpretation of results will be in the peer-reviewed literature.

 

This image shows the kinematic comparison of the Q6s ATD (top) and exemplar 6-year-old volunteer (bottom) at initial position, mid-motion, and maximum excursion in a lateral low-speed impact. At mid-motion, the Q6s exhibited lateral head rotation, whereas the volunteer’s head remained upright.

 

Year 1: 2012-2013 & Year 2: 2013-2014

Because children are not simply “small adults,” the mitigation of injuries from motor vehicle crashes requires biofidelic pediatric anthropomorphic test devices (ATDs), or child crash test dummies, to effectively design and evaluate automotive safety systems. Previous CChIPS research evaluated the biofidelity of pediatric ATDs by comparing their response in frontal crashes to similar tests of restrained 6- to 14-year-old pediatric human volunteers. Although frontal crashes are most common, side impact crashes have a higher mortality and injury burden for rear seat occupants. Far-side impacts in particular account for 43 percent of Abbreviated Injury Scale (AIS) 3+ injuries and 25 percent of lateral impact fatalities. Therefore, there is a growing need to evaluate the biofidelity of the pediatric ATDs in far-side impacts by comparing them to biomechanical response data from real children, which is extremely limited in the literature. Through additional funding by CChIPS member TK Holdings Inc., CChIPS researchers have collected data on the kinematics and kinetics of restrained pediatric human volunteers, ages 9 to 14 years, in low-speed lateral and oblique far-side sled tests.

The current study leveraged this previous work and had the following aims: 1) to expand the age range of lateral and oblique far-side pediatric volunteer data collection to include 6- to 8-year- olds, and 2) to continue the current line of ATD comparison research. Specifically, this includes comparisons between pediatric ATDs and age matched pediatric volunteers ages 6 to 14 years in lateral and oblique loading conditions.

Low-speed, far-side oblique and lateral sled tests were conducted using the Hybrid III and Q-series 6 and 10-year-old side impact ATDs, as well as the SID-IIs and WorldSID 5th percentile female. The ATDs were restrained by a lap and shoulder belt equipped with a pre-crash belt pre-tightener and photo-reflective targets were attached to the head, spine, shoulders, and sternum.

The ATD data were compared with previously collected 9- to 14-year-old volunteer data and newly collected 6- to 8-year-old volunteer data tested with similar methods. Metrics of comparison included head, spine and torso excursion, seat belt and seat pan reaction loads, belt-to-torso angle, and shoulder belt slip-out.

In general, the ATDs overestimated lateral excursion in both impact directions and underestimated forward excursion of the head and neck in oblique impacts compared to the pediatric volunteers. Additionally, the effect of belt pre-tightening on occupant kinematics was greater for the ATDs than the volunteers. Overall, the findings suggest that the pediatric ATDs exhibit sub- optimal biofidelity under these loading conditions. Additionally, though some metrics were statistically similar between the ATDs, no particular ATD was substantially more biofidelic than another.

To our knowledge, this is the first study to evaluate the biofidelity of the 6- and 10-year-old pediatric ATDs in side impacts by comparing their response to child volunteers. These data provide insight into the biofidelity of the pediatric ATDs in far-side impacts and have important implications for the design and evaluation of low-speed countermeasures.

 

Project Team Members:
Caitlin Locey, BS, The Children’s Hospital of Philadelphia; Mathew R. Maltese, PhD, The Children’s Hospital of Philadelphia; Wenli Wang, MS, The Children’s Hospital of Philadelphia; Kristy Arbogast, PhD, The Children’s Hospital of Philadelphia

Students:
Dandi Zhu, The University of Pennsylvania; Dakota Jones, Syracuse University

IAB Mentors:
Doug Longhitano, American Honda Motor Co., Inc.; Kazuo Higuchi, TK Holdings Inc.; Schuyler St. Lawrence, Toyota Motor North America Inc.; Richard Bandstra, Volkswagen Group of America

About This Center

This Center is made possible through a grant from the National Science Foundation (NSF) which unites CHOP, University of Pennsylvania, and The Ohio State University researchers with R&D leaders in the automotive and insurance industries to translate research findings into tangible innovations in safety technology and public education programs.

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