The Effects of Initial Spinal Configuration on Pilot Ejection
Abstract
The effect of initial spinal alignment on the location and magnitude of maximum vertebral stress during ejection was studied using the Orne-Liu discrete parameter model of the spine. Face curtain, shoulder harness, and seat back restraints were added to the model as linear springs. Spinal alignment data used were from x-rays of a 5th, 40th, and 95th percentile (sitting height) man seated in the MK-J5(D) ejection seat under static conditions. Maximum normal stresses were shown to occur at L1(5th), T12(40th) and T9(95th) with face curtain and shoulder harness restraint. Results indicated that a state of nearly uniform axial stress exists in the column during ejection and thus the location of maximum bending stress dictates the spinal location of the maximum normal stress. Hence, initial spinal alignment, in terms of the curvature of the column, is a major determinant of the location and magnitude of maximum normal stress for a given set of restraints.
Document Details
- Document Type
- Technical Report
- Publication Date
- Oct 01, 1973
- Accession Number
- AD0780847
Entities
People
- Ronald R. Hosey
- Uwe R. Pontius
- Y. K. Liu
Organizations
- United States Army Aeromedical Research Lab