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NHTSA Task Order 4: Building on the findings of Partners for Child Passenger Safety to Develop a more Accurate Child Anthropomorphic Test Dummy (ATD)

Study Background

Child ATDs are largely developed by size-scaling adult crash dummies down to child-size, with minimal consideration for the structural differences between a fully developed adult body, and a child’s developing body. Accordingly, the research gathered through the analyses conducted as part of NHTSA Task Order Four are aimed at developing a more human-like child ATD that will help engineers to better evaluate the response of a child’s body to the forces at play during crash impact.

Study Goals

Engineers at the Center looked to address this discrepancy by addressing the three body regions where crash injuries occur most often in children, and are the most serious: the head, neck/ cervical spine, chest, and abdomen. There are four main research goals within Task Order Four; each is its own research project:

Individual Project Details

Assessing the link between AIR and Pediatric Abdominal Injury Using the Hybrid III 10-year-old ATD
  • Background

    The issue of seat belt syndrome, although identified decades ago, has received increased attention recently as focus has been placed on reducing the risks of seat belt syndrome in children. The number of children at risk of developing seat belt syndrome following a crash is high due to the large number of children being inappropriately restrained by adult seat belts.

    To address the large number of pediatric abdominal injuries, the National Highway Safety Administration (NHTSA) is discussing the inclusion of an abdominal criterion into regulations related to child anthropomorphic dummies (ATD) and child restraint safety. Because human pediatric response and injury information is scarce, the agency is limited to proposing ATD-based criteria that serve to minimize the exposure of the ATD abdomen to loading by the vehicle belt system. The Vehicle Research & Test Center (VRTC) has proposed one such measure, Abdominal Impulse Ratio (AIR), which uses a combination of time-based impulse calculations from the ATD’s iliac compression and lumbar shear forces to identify quantitatively whether the lap belt is loading the abdomen excessively

  • Objective and Methods

    The objective of analysis is to investigate whether there is a link between Hybrid III 10-Year-Old ATD-based abdominal criteria and pediatric injuries suffered in real-world crashes; and, if there is a link, to determine at what value the criteria limit should be set to minimize the chance of severe abdominal injury.

    In order to achieve these objectives, specific aims were as follows:

    • Assess the utility of AIR and other potential Hybrid III 10-Year-Old ATD-based criteria to predict pediatric abdominal injury in simulated case reconstructions in which the abdomen is loaded by the vehicle restraint system.
    • Define a no injury vs. injury threshold for one or more of these criteria that can be used in the NHTSA testing to assess restraint performance with respect to abdominal protection.
  • Findings

    This research is in progress

Testing the validity of the SIMon head injury evaluation tool using scale 6-year-old ATD data
  • Background

    Head injuries sustained during crashes can result in a traumatic brain injury and have devastating consequences to human health. The current method of evaluating head injuries is the Head Injury Criteria (HIC), which is based on linear acceleration alone. SIMon (Simulated Injury Monitor) is software developed by NHTSA to advance the interpretation of head injury mechanisms based on kinematics and kinetic data using a finite element head model. This model has been applied and evaluated for use in adults only.

  • Objective and Methods

    This study aims to test the validity of the SIMon adult head model when using scaled 6-year-old data for dead injury prediction

  • Findings:

    This research is in progress

Pediatric thoracic stiffness- improving the accuracy of the pediatric ATD
  • Background

    Pediatric ATD (child crash test dummies) are largely developed by size-scaling adult ATD down to child-size, with minimal consideration for the structural changes the human body undergoes throughout the development process. The thoracic (chest) region is not fully developed in children and will not withstand the same crash forces as with adults, so further testing is needed to develop a more accurate thoracic region in the pediatric ATD.

  • Objective and Methods

    The goal of this study is to provide pediatric chest-deflection measurements in order to develop a more human-like child ATD. This is done by extracting biomechanical thoracic stiffness data from in-hospital cardiopulmonary resuscitation (CPR). The magnitude of chest compressions during CPR are similar to those experienced in a vehicle crash, and using a novel FDA-approved force-deflection sensor for improving the quality of CPR, we can extract the force applied to the chest and the resulting chest deflection. This force-deflection data can then be used to develop a more accurate child test dummy.

  • Results

    This research is in progress

Passive Range of Motion of the Pediatric Cervical Spine
  • Background

    Head injury is the most frequently cited cause of death in fatal child motor vehicle crashes (MVC) and the most frequent injury in child crashes in which the victims survived. The pediatric ATD is a key tool for vehicle manufacturers in the development of safety systems, and the range of motion of the neck is an important factor in determining trajectory of the dummy head and thus the potential severity of a head strike to the interior of the vehicle.

  • Objective and Methods

    The study will extract the passive range of motion of the human neck, which in turn can be used as a design guideline for child crash test dummies.

    Given the importance of a human-like or biofidelic neck, this study focuses on sub-injurious (non-injury causing) loading to the head/neck complexes of healthy volunteers. A special device applies a non-injurious 1g inertial load to the restrained body and an optical target-tracking system measures the movement response of the body to this load.

    Using Electromyography (EMG), muscular activity is minimized through audio-feedback coaching to the subject, thus simulating the vehicle occupant who is unaware of an impending crash and this is not bracing for impact.

  • Results

    This research is in progress

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