STATIC AND DYNAMIC FINITE-ELEMENT ANALYSES OF AN IDEALIZED STRUCTURALMODEL OF VERTEBRAL TRABECULAR BONE

An idealized three-dimensional finite element model of a rodlike trabe cular bone structure was developed to study its static and dynamic res ponses under compressive lending, considering the effects of bone marr ow and apparent density. Static analysis of the model predicted hydrau lic stiffening of trabecular bone due to the presence of bone marrow. The predicted power equation relating trabecular bone apparent elastic modulus to its apparent density was in good agreement with those of t he reported experimental investigations. The ratio of the maximum stre ss in the trabecular bone tissue to its apparent stress had a high val ue, decreasing with increasing bone apparent density. Frequency analys es of the model predicted higher natural frequencies for the bone with out marrow than those for the bone with marrow. Adding a mass relative ly large compared to that of bone rendered a single-degree-of-freedom response. In this case, the resonant frequency was higher for the bone with marrow than that for the bone without marrow. The predicted vibr ational measurement of apparent modulus was in good agreement with tha t of the static measurement, suggesting vibrational testing as a metho d for nondestructive measurement of trabecular bone elastic moduli.