Application of molecular dynamics simulations for the generation of dense concrete mesoscale geometries

• Published in: Computers & structures Vol. 158; pp. 274 - 284
• Main Authors: Titscher, Thomas, Unger, Jörg F.
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.10.2015
• Subjects: Aggregates; Algorithms; Computer simulation; Concrete mesostructure; Concretes; Mathematical analysis; Mesoscale geometry; Mesoscale phenomena; Molecular dynamics; Molecular structure; Polydisperse sphere packing; Molecular dynamics; Polydisperse sphere packing; Mesoscale geometry; Concrete mesostructure
• ISSN: 0045-7949; 1879-2243
• DOI: 10.1016/j.compstruc.2015.06.008

•Fast generation of mesostructures for concrete using a molecular dynamics simulation.•Significant increase of volume fraction compared to commonly used methods.•Efficient optimization techniques to handle a large number of particles.•Introduction of a minimal particle distance to ensure undistorted FE-meshes. The problem of polydisperse sphere packings is applied to concrete mesoscale geometries in finite sized specimens. Realistic sphere diameter distributions are derived from concrete grading curves. An event-driven molecular dynamics simulation using growing particles is introduced. Compared to the widely used random sequential addition algorithm, it reaches denser aggregate packings and saves computation time at high volume fractions. A minimal distance between particles strongly influences the maximum aggregate content. It is essential to obtain undistorted elements when meshing the geometry for finite element simulations. The algorithm maximizes this value and produces meshable concrete mesostructures with more than 70% aggregate content.