How Does The Bone Shaft Geometry Affect its Bending Properties?

Abstract

Abstract:In this research, ten fresh specimens of sheep tibiae were provided from slaughtered animals. Whole bone specimens were loaded in three-point bending according to standard wet bone test protocols. Mechanical properties were determined and compared with the results which were obtained from two dry bone tests. The results showed that fracture bending moment and bone extrinsic stiffness had significant relations with fracture cross-section dependent parameters (i.e., cross-section area and area moment of inertia). Where, fracture energy and ultimate strength did not have such a relation with these parameters. Finite element modeling of bone shaft was made with simplified geometry (neglecting cross-section variations along bone shaft) in two steps: First, by elliptical crosssection and second, by circular cross-section, assuming linear elastic and isotropic properties for the specimens. Elastic (Young's) modulus and fracture load, evaluated from curves obtained from tests, were applied to the finite element model and close results of maximum stress in both test specimen and first (elliptical cross-section) model showed up. There was an average difference of about 2% between ultimate strength of wet bone specimens and maximum (tensile) stress occurred in the elliptical models. However, this value for circular models was about 16%.

Elucidation of the radius and ulna fracture mechanisms in toy poodle dogs using finite element analysis

“…Based on the beam theory, the resulting stresses depend on the CSA perpendicular to the load when a load is applied axially to a beam. A smaller CSA produces higher stresses for the same applied force [35,40]. The study found that toy poodles CSA of the radius consistently exhibited reduced dimensions compared to those observed in dachshunds (Table 2), indicating their increased risk of fractures due to higher bone stress levels during loading conditions.…”

Experimental assessment of biomechanical properties in human male elbow bone subjected to bending and compression loads

“…The area moment of inertia for tubular structures is higher and hence can result in the prediction of lower bending strength. 47 Nevertheless, this method is good for a first approximation. As reported by Motoshima, the bending modulus of humerus, ulna, and radius bones was 10, 15.39, and 15.88 GPa, respectively.…”

“…51,52 Research groups have experimented on the fracture toughness both on sectioned-bone samples 25,26,53,54 as well as on whole-bone samples. 43,47,55 In the case of the characterization of human elbows for fracture toughness, whole-bone samples have not been reported yet. Research groups have used various ASTM standards for mechanical testing of bones such as D-790 for bending, 56 C-469 and D-1621 for compression testing, 44,57 and E-399 and E-1820 18,30,53,58 for fracture toughness.…”