A domain separate method of developing orthogonal hexahedron finite element mesh model from CT/μCT slice image files

The finite element (FE) analysis of bone structure starts with the construction of an accurate FE mesh models. The popular method to acquire a realistic geometry is using the commercial software Mimics which has powerful reconstruction ability from CT/μCT slice image files. Then a FE mesh model can be established based on the constructed geometry model with a meshing process. However, when an orthogonal hexahedron finite element mesh model was required under certain circumstances, the mainstream method is no longer sufficient. The generic method that directly transforming pixels into the orthogonal hexahedral element was relatively simple, but the direction was fixed, it must be perpendicular to the scan direction. Therefore, we propose a generic method which was called Domain Separate Method in response to this issue. The main idea of Domain Separated Method (DSM) was constructing a large enough pre-meshed domain with orthogonal hexahedron elements at first, then separated the hexahedron elements based on the STL model derived from Mimics. The separation process was proceed by implemented a self-coding intersection detection program with volume adjustment function. The numerical examples show that the DSM is efficient and accurate, and robust to scan orientation.