A Viscoelastic Finite Element Model of the Human Intervertebral Joint

摘要

The combined mechanical stresses on aircrewmen have become increasingly acute as technological developments extend the flight envelopes of our high performance aircraft. Limitations on the design of this type of aircraft are frequently dictated by human tolerance. The concept of an analytical model to evaluate the biomechanical response of the human intervertebral joint, under the influence of long term axial compressive loading, is important in assessing the load carrying capability of normal and diseased vertebral segments. It has been experimentally demonstrated that healthy intervertebral joints are composed of materials which exhibit creep characteristics. This investigation is significant because it presents a study of the time dependant behavior involved. An axisymmetric finitie element model is employed which incorporates a linear viscoelastic constitutive relation for the intervertebral disc. Viscoelastic material constants are found by matching one-dimensional data with the two-dimensional model. Results are presented depicting displacement profiles and stress redistributions occurring as a consequence of the inclusion of these viscoelastic parameters which, for the first time, simulate the actual human response to high compressive loads over a specific time span. (Author)