Experimental limitations of quasi-linear theory, and a method for reducing these effects

The quasi-linear model has been applied to predict the in vitro responses of the human cervical spine in torsion. This model was developed by approximating a true relaxation test with a finite rate ramp and hold. The performance of this model was good, reaching the 99% confidence level (r = 0.9288); however, the model tended to underestimate hysteresis energy, and dynamic torsional stiffness. To reduce the detrimental effects of the finite rate approximation, an extrapolation, deconvolution technique has been developed. The quasi-linear model based on this derivation showed improved predictive ability (t = 0.9451), and a more accurate prediction of hysteresis energy. This technique is therefore recommended for use in other applications of the quasi-linear model where rapid rate ramp and hold testing is not experimentally feasible.

Duke Scholars

Author Barry S. Myers Biomedical Engineering

Author James H. McElhaney Biomedical Engineering