An investigation of bovine lumbar vertebral body stiffness with experimental measurement and finite element modelling
Date
1994
Authors
Sanders, Michael Morrison
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Abstract
Geometrical and structural properties of bovine vertebral bodies were measured from laboratory specimens and used to develop finite element method (FEM) models. The material properties (i.e. moduli) in the models were taken from recent published reports. To validate the models, compression tests were performed on bone specimens using an MTS testing machine, and stiffness was compared to that produced from the models.
For one out of the three vertebral bodies tested, the FEM model predicted a stiffness within the range measured. But by using parameters slightly lower than the mean, two of the three models produced stiffness comparable to the experimental. Though accurate measurement of geometry was shown to improve stiffness predictions, the cortical shell thickness was the most sensitive input parameter affecting stiffness. The models indicated that most of the vertebral body stiffness is due to the cortical shell. But the shell thickness was troublesome to measure in the laboratory. With more efficient and accurate measurement of geometry and bone density (as obtained with Quantitative Computed Tomography, QCT), such FEM models may accurately predict strength and stiffness of human bone in the future.