A new software tool (VA-BATTS) to calculate bending, axial, torsional and transverse shear stresses within bone cross sections having inhomogeneous material properties

Abstract

Introduction: This study introduces, validates and demonstrates a new automated software tool (VA-BATTS) to calculate bone stresses within a bone cross section subjected to bending, axial, torsional and transverse shear far-field loading conditions, using quantitative computed tomography (QCT) data.

Methods: A QCT image is imported and processed to generate a 2D finite element (FE) mesh of the bone with inhomogeneous (CT-based) transversely isotropic material properties. Bending and axial stresses are determined using inhomogeneous beam theory; torsional and transverse shear stresses are calculated using a new 2D FE formulation.

Results: Validation studies show excellent agreement between results obtained using VA-BATTS and results obtained using analytical 2D models and inhomogeneous 3D FE models.

Discussion: Out-of-plane bone stresses can be accurately calculated using a 2D analysis. Material inhomogeneity can have a marked effect on predicted stresses. In three-point bending experiments, transverse shear may present important contributions to the failure potential.

The software is available at https://simtk.org/home/va-batts.

Keywords:

• bone stress calculation
• inhomogeneous material properties
• transverse shear
• torsional shear
• finite element analysis
• bone mechanical properties

Acknowledgements

This study received funding support from the Department of Veterans Affairs, Rehabilitation Research and Development Service (project B3860R). The authors would also like to thank Derek Lindsey and Dana Carpenter for providing CT scans of the bones.