DYNAMIC RESPONSE OF AN L2-L3 MOTION SEGMENT TO COMPRESSIVE CYCLIC LOADING USING A NONLINEAR VISCOELASTIC FINITE ELEMENT MODEL

Abstract

The axial compressive cyclic loading was applied to a nonlinear viscoelastic finite element model of an L2-L3 motion segment to investigate its dynamic response. In this validated model, the material properties of the anuius matrix, anuius fibers and nucleus pulposus (NP) have been represented by the viscoelastic constitutive laws. The detailed stress-strain analysis of the motion segment under cyclic loading was performed to quantify the load sharing amongst passive elements. The cyclic loading encountered due to exposure of vibration or during driving has been implicated as a risk factor for occupational low back disorders (OLBD). The cyclic axial compressive loading was controlled, peak to peak, from 600 N to 1000 N at 0.5 Hz for 15 cycles (30 seconds). The results indicated that the axial stiffness of the motion segment decreased, while intradiscal pressure (IDP) and the strain of the anuius fiber increased.