Neck Pendulum Test Modifications for Simulation of Frontal Crashes

Pediatric Anthropomorphic Test Devices (ATDs) are valuable tools for assessing the injury mitigation capability of automotive safety systems. The neck pendulum test is widely used in biofidelity assessment and calibration of the ATD neck, and neck moment vs. angle response requirements are the metrics typically derived from the test. Herein, we describe the basis and methods for modifying the neck pendulum such that it more closely reflects base of the neck accelerations observed by a restrained three-year old ATD in a frontal crash. As a measure of base of the neck acceleration, the x-direction chest acceleration from thirty-one restrained Hybrid III three-year-old ATDs in vehicle frontal crash tests were analyzed. The standard neck pendulum yielded a mean peak acceleration that is 1.2x the peak of vehicle base of the neck accelerations, 1.6x the average, and 0.24x the duration. Cost effective modifications to the standard neck pendulum test apparatus produced longer duration pulses that are more reflective of the frontal crash test environment. The modifications to the pendulum included the addition of springs and adjustments to the honeycomb-to-pendulum impact location, which yielded pendulum accelerations that were 0.61x the peak, 0.8x the average, and 0.82x the duration of the vehicle base of the neck accelerations. The addition of high-speed videography to the measurement parameters allows for the assessment of neck bending angles and in particular, the head lag phenomenon exhibited in volunteer and PMHS studies.