The Effect of Initial Curvature on the Dynamic Response of the Spine to Axial Acceleration
Abstract
A majority of the studies on the dynamic response of the human torso have considered uni-axial models wherein the initial curvature of the spine is ignored. A detailed discrete parameter vertebral response model incorporating the variable geometry of the spine and subjected to pilot ejection simulated impact conditions has been recently investigated by Orne and Liu. In this work, a simple continuum representation of the spine is formulated and the resulting boundary value problem is solved for the axial and lateral (bending) dynamic response. The assumed model is a constant cross-section, sinusoidally curved, elastic beam with an end mass subjected to an axial acceleration at the other end. The effects of transverse shear and rotational inertia are ignored in the model. The equation governing axial displacement is a non-homogeneous wave equation subjected to non-homogeneous boundary conditions. The governing approximate equation for the lateral deflection is a non-linear second order differential equation with variable coefficients. Short time solutions for these equations are obtained to demonstrate the effect of initial curvature on the spinal dynamic response. Numerical results indicate that the dynamic bending stress is significant in comparison to the axial dynamic stress.
Document Details
- Document Type
- Technical Report
- Publication Date
- Dec 01, 1971
- Accession Number
- AD0740458
Entities
People
- S. H. Advani
- T. F. Li
- Y-c. Lee
Organizations
- Air Force Research Laboratory