Damage analysis of human cortical bone under compressive and tensile loadings

Abstract

Developing advanced fracture tools can increase the understanding of crack growth trajectories in human cortical bone. The present study investigates fracture micromechanics of human cortical bone under compressive and tensile loadings utilizing a phase field method. We construct two-dimensional finite element models from cortical microstructure of a human tibia cross section. We apply compression on the cortical bone models to create compressive microcracks. Then, we simulate the fracture of these models under tension to discover influential parameters on microcracks formation and post-yielding behavior. The results show that cement lines are susceptible sites to damage nucleation under compression rather than tension. The findings of this study also indicate a higher accumulation of initial damage (induced by compression) can lead to a lower microscopic stiffness as well as a less resistant material to damage initiation under tension. The simulations further indicate that the post-yielding properties (e.g., toughness) can be dependent on different variables such as morphological information of the osteons, the initial accumulation of microcracks, and the total length of cement lines.

Keywords:

• Cortical bone
• crack propagation
• tension
• compression
• phase-field modeling

Acknowledgements

The authors would like to thank Dr. Lamya Karim and Taraneh Rezaee at the University of Massachusetts Dartmouth for supplying the cortical bone samples. We also would like to thank Dr. Theresa Freeman from Thomas Jefferson University for providing access to her laboratory, equipment, and resources to perform the staining procedure. Additionally, we would like to acknowledge the Drexel University Research Computing Facility for the use of their high-performance computing resources (PROTEUS: the Drexel Cluster). This work was financed by the faculty start-up finding from the Department of Mechanical Engineering and Mechanics at the Drexel University. Ebrahim Maghami was also supported in part by a grant from Commonwealth of Pennsylvania, Department of Community and Economic Development (Contract No. C000072548 provided by the Manufacturing Pennsylvania Innovation Program to Carnegie Mellon for the project titled: Damage-tolerant Design of UHPC composites).

Disclosure statement

No potential conflict of interest was reported by the authors.

Notes

1 L_tot is the sum of the lengths of every crack present in the model. This quantity can be comprised of one long crack or many shorter cracks.

Additional information

Funding

The Commonwealth of Pennsylvania, Department of Community and Economic Development.