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Volume 45 Number 8, 2008
   Pages 1227 — 1236

Abstract - Estimation, simulation, and experimentation of a fall from bed

Brian W. Schulz, PhD;1* William E. Lee III, PhD;2 John D. Lloyd, PhD1

1Rehabilitation Research and Development Research Enhancement Award Program, James A. Haley Veterans'
Hospital, Tampa, FL; 2College of Engineering, University of South Florida, Tampa, FL

Abstract — Computer simulations using multibody models have been extensively applied to vehicular crash testing but have rarely been used to investigate falls. This article investigated planar and three-dimensional simulations of a single physical test of a Hybrid III anthropomorphic test dummy falling from a bed and compared them with a common estimation method. The effects of initial model position and velocity on simulated peak resultant head deceleration and head impact criterion (HIC) were determined while all contact and model parameters were held constant. Improving body position at impact and impact velocity direction both improved results. Simulating the entire fall instead of only the impact further improved simulation output, but HIC was consistently overestimated because of inaccurate contact parameters. These results show that accurate kinematics are crucial to accurate simulation output but improved contact parameters and thorough validation of experimental data are required before any fall simulation should be used to extrapolate findings beyond what is experimentally practical or possible.

Key words: accelerometer, anthropomorphic test dummy, bed, biomechanics, deceleration, fall, head impact, head injury, LifeMOD, simulation.


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