title: Thoracic injury metrics with side air bag: stationary and dynamic occupants.
abstract: OBJECTIVE
  Injury risk from side air bag deployment has been assessed using stationary out-of-position occupant test protocols. However, stationary conditions may not always represent real-world environments. Therefore, the objective of the present study was to evaluate the effects of torso side air bag deployment on close-proximity occupants, comparing a stationary test protocol with dynamic sled conditions.
  
  
  METHODS
  Chest compression and viscous metrics were quantified from sled tests utilizing postmortem human specimens (PMHS) and computational simulations with 3 boundary conditions: rigid wall, ideal air bag interaction, and close-proximity air bag deployment. PMHS metrics were quantified from chestband contour reconstructions. The parametric effect of DeltaV on close-proximity occupants was examined with the computational model.
  
  
  RESULTS
  PMHS injuries suggested that close-proximity occupants may sustain visceral trauma, which was not observed in occupants subjected to rigid wall or ideal air bag boundary conditions. Peak injury metrics were also elevated with close-proximity occupants relative to other boundary conditions. The computational model indicated decreasing influence of air bag on compression metrics with increasing DeltaV. Air bag influence on viscous metric was greatest with close-proximity occupants at DeltaV = 7.0 m/s, at which the response magnitude was greater than linear summation of metrics resulting from rigid impact and stationary close-proximity interaction.
  
  
  CONCLUSIONS
  These results suggest that stationary close-proximity occupants may not represent the only scenario of side air bag deployment harmful to the thoraco-abdominal region. The sensitivity of the viscous metric and implications for visceral trauma are also discussed.
authors: Department of Biomedical Engineering, Marquette University, Milwaukee, Wisconsin, USA. jhallman@mcw.edu
authors: Jason J
authors: JJ
authors: Hallman
authors: N
authors: N
authors: Yoganandan
authors: Frank A
authors: FA
authors: Pintar
mesh_terms: D000063:Accidents, Traffic / Q000706:statistics & numerical data*; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D017278:Air Bags / Q000009:adverse effects*; D001696:Biomechanical Phenomena; D002102:Cadaver; D003198:Computer Simulation; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D018570:Risk Assessment; D013898:Thoracic Injuries / Q000209:etiology*