Multiaxial Viscoelasticity and Damage Effects in Vertebral Trabecular Bone

INTRODUCTION: The rapid expansion of the at-risk population for pathological fracture has led to increased interest in the ability to predict the mechanical behavior of trabecular bone as it relates to routine nontraumatic loading. A large body of work has established that the mechanical behavior of cancellous bone, particularly stiffness and strength under monotonic loading, is strongly dependent on both density and architecture measures of the bone. The nonlinear mechanical behavior that is evident well before material yield and failure [1] is much less studied. We utilized a low-cycle experimental protocol to examine the constitutive response of vertebral trabecular bone. Within the larger goal of incorporating this behavior in stress analysis models, we developed an orthotropic damaging viscoelastic model to describe the effects of damage and viscous response at low-strain.