Biomechanical Behavior Characterization and Constitutive Models of Porcine Trabecular Tibiae

SIMPLE SUMMARY: In surgery, when it comes to repairing a trauma injury, there are many variables that must be taken into account. For this reason, to study the possible effects of modifying any of the variables, it is necessary to approach the problem using numerical methods. In this work, the behavior of porcine trabecular bone, which is the most involved in this type of surgery, is experimentally analyzed to obtain constitutive models of behavior when using alternative techniques that simulate reality, such as the finite element method. Experimental compression tests were carried out, obtaining the mechanical properties of the material and the most suitable models were defined. The predictions of these models have been compared with the experimental results, thus choosing the most suitable one. ABSTRACT: Customizing any trauma surgery requires prior planning by surgeons. Nowadays, the use of numerical tools is increasingly needed to facilitate this planning. The success of this analysis begins with the definition of all the mechanical constitutive models of the materials implied. Our target is the trabecular bone because almost all trauma surgeries are closely related to it. This work focuses on the experimental characterization of porcine trabecular tibiae and defining its best constitutive model. Therefore, different types of compression tests were performed with tibia samples. Once the potential constitutive models were defined, stress–strain state from numerical approaches were compared with the corresponding experimental results. Experimental results from uniaxial compression tests showed than trabecular bone exhibits clear anisotropy with more stiffness and strength when it is loaded in the tibia longitudinal direction. Results from confined compression tests confirmed that the plastic behavior of trabecular bone depends on the hydrostatic and deviatoric invariants, so an alternative formulation (crushable foam volumetric (CFV)) has been proposed to describe its behavior. A new method to obtain CFV characteristic parameters has been developed and validated. Predictions of the CFV model better describe trabecular bone mechanical behavior under confined conditions. In other cases, classical plasticity formulations work better.