Innovative simulation tool for bone and bone biomaterials, based on enhanced CT-data exploitation

Objectives


The project BIO-CT-EXPLOIT covers realization of commercializable software related to a very recent, scientific approach, which provides a fully anisotropic and inhomogeneous material description of natural bone tissue and bone biomaterials, from Computer Tomography data: Therefore, we will use the physical significance of Hounsfield units and corresponding X-ray attenuation coefficients for the (chemical) composition of the considered voxel, in combination with continuum micromechanics material models, in order to convert the chemical composition into elastic tensors. More specifically, we will realize the following steps:

  • Based on de-convolution techniques, we will separate machine- and processing-related artefacts from X-ray attenuation coefficients. Based on voxel average rules for the attenuation coefficients, we will assign to each voxel the volume fractions of the material constituents.
  • By means of micromechanical models for natural bone and bone biomaterials, based on stiffness properties of the material constituents, we will convert the aforementioned volume fractions into voxel-specific orthotropic,transversely isotropic, or isotropic stiffness tensor components corresponding to a base frame coinciding with the principal material directions.
  • We will derive the material trajectories from the geometry and texture of selected objects, and collect all Finite Element-specific stiffness tensors expressed in one global coordinate system relevant for the investigated object.

This comprehensive exploitation of CT data, based on sound (chemo-)physical principles rather than on empirical approximations, will lead the way to more realistic and reliable prediction of the mechanical behaviour of bone organs and biomaterials. Namely, for the first time, the complete elastic behaviour of the bone (bio)material (in terms of full orthotropic, transversely isotropic, or isotropic elasticity tensors) will be assigned to the structural model on a voxel-per-voxel basis.

The aforementioned working steps are supported by production and CT imaging of biomaterials as typical state-of-the-art objects to be investigated by the new software tool , and by (micro-)mechanical and acoustical testing of these biomaterials as to check the relevance and reliability of the developed simulation tools.

The latter will beneficially improve the SMEs´ portfolios concerning image analysis, mesh generation, finite element modeling, and biomaterial production.