Mesoscale FEM approach on cemented sand : challenges and implementation of high order elements

Citation
10th European Conference on Numerical Methods in Geotechnical Engineering: Proceedings (2023)
Contribution to Conference
10th European Conference on Numerical Methods in Geotechnical Engineering, NUMGE 2023  
Publisher DOI
10.53243/NUMGE2023-96
The rapid development of 3D imaging techniques, combined with image analysis, has enabled the quantification of the morphology of multiphase media. One step beyond, the ability to mesh the captured geometry allows the numerical testing of the digital twin, proven to be a valuable numerical tool in material investigation and micro-macro implementations. The scope of this study is the implementation of a finite element discretization of 3D images of cemented sand. The proposed method of the image adapted meshing technique has been implemented and linked to the FE framework of the commercial code ABAQUS Standard. The evaluation of the results demonstrates both accuracy and efficiency in capturing the causes that trigger matrix cracking and grain crushing. Furthermore, computational challenges of excessive stiffness and parasitic stresses are addressed and solved by increasing the order of the elements used. This attempt required the development of an add-on feature to the Delaunay triangulation algorithm, which enriches constant strain tetrahedral elements with nodes at the midpoints of their edges and upgrades their shape functions from linear to quadratic.
Subjects
cemented sand
high order tetrahedral elements
mesoscale FEA
X-ray CT
DDC Class
620: Engineering
690: Building, Construction