Open Access

ARTICLE

Dynamic Properties of Cortical Bone Tissue: Izod Tests and Numerical Study

Adel A. Abdel-Wahab¹, Angelo Maligno¹, Vadim V. Silberschmidt¹

1 Wolfson School of Mechanical and Manufacturing Engineering, Loughborough University, Le-icestershire, U.K.

Computers, Materials & Continua 2010, 19(3), 217-238. https://doi.org/10.3970/cmc.2010.019.217

Abstract

Bone is the principal structural component of a skeleton: it assists the load-bearing framework of a living body. Structural integrity of this component is important; understanding of its mechanical behaviour up to failure is necessary for prevention and diagnostic of trauma. In dynamic events such as traumatic falls, involvement in car crash and sports injuries, bone can be exposed to loads exceeding its structural strength and/or fracture toughness. By developing adequate numerical models to predict and describe its deformation and fracture behaviour up to fracture, a detailed study of reasons for, and ways to prevent or treatment methods of, bone fracture could be implemented. This study deals with both experimental analysis and numerical simulations of a cortical bone tissue and its response to dynamic loading. Two areas are covered: impact Izod tests for quantifying a bone's behaviour under impact loading, and a 2-D finite-element model simulating these tests. In the first part the effect of three different parameters - a cortex position, a notch depth and an energy level - on the bones tissue's response to dynamic loading was investigated. Specimens cut from anterior, posterior, medial and lateral cortex position were tested at two different levels of energy for two notch depths. In the second part, a 2D numerical model for the impact Izod test was developed using the Abaqus/Explicit finite-element software. A fully transient formulation employs an initial angular velocity of the hammer together with the real dimensions and material properties of the specimen and the impacting hammer. Three different constitutive material models - linear-elastic, elastic-plastic and viscoelastic - were implemented to compare respective results for impact parameters and fracture force. The obtained experimental results emphasize that bovine femur cortical bone has a nearly uniform fracture energy character with regard to cortex position. The simulation results showed a good agreement of the viscoelastic model with the experimental data.

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