The analytical modolling of cr eep re sponse phenomena of intervertebral discs subjected to a constan t axial compre ssive load is atte mpted ~y using Kolvin-solid models. A mathe matic al analy sis scheme is propo sed for unique model idsntUj catto n wherein exact para meter solution s are deve loped for the one-Kelvin -unit model , the t hree-parameter-so lid model , and the two-Kelvin-unit model. In additio n , a metho d is presented by which the associated Young 's moduli and viecosity

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... icient s for an identified model are obtainab ' -. Moot importantly, uniqu e para meter value s are obtained for the three-parameter-so lid by utilising exact model parameter solution s on exper imental strain , E ( t ) , da ta . This particular model is observed to yield theor etical strain , E (t) caii values tha t are wit hin an average error of 3.48% of the exper imentally measured values, E ( t )~x p~ for different intervertebral discs. Further, mechanical properties of the inte rv ertebral discs are obtained by u sing the values of the three-p arameter-solid model parameters to calculat e the associated Young ' s moduli and viscosity coefficient. The appropriate applications, data limitations, and possible gcner a.lizat ions of thi s exact analysis scheme are fully discussed, along with sugge stions for future investigatory effo rts ,~~~~~~~~~~ --I, ~~~~~~~. -. AIR FORCE OFFICE OF SClEN TIF1~ r :~icu (AFSC ) ' --~~Ñ OT ICE OF TRAN~MtTTMI T~ ~~~~~ ~~~~~~~~~~~ -T his te chii~-~~~l ; 'c~'~~r~ ~~~ bti~~~ :' -~v .~ ' and is ç~ ã pproved ' or ~~~I~~C r -1 :~~S~ ~~. . ~~J -L ( 7 b ) . \ r' \ -D t st r ib t A tt 0~1 i~ u: i1 ir~it e d .