Method and Software for Modeling the Building Materials as Dispersions

Particle system dynamics is the well known method that can be used in wide range of spatial scales – from molecular to astronomic. However, numerical experimentation with constructional composites requires adequate representation of peculiar forces that are due to solvation shells, steric conditions and technological actions. Thus, despite the fact that there is currently a lot of software suitable for particle system dynamics, the existing software is of limited use in constructional material science. In the present work we have developed the proper model of building material as dispersion with solvation shells. The software implementation of the developed model is also briefly described. The model and software were already successfully used in several basic and applied research works in material science. Introduction During the last decades, there was a considerable progress in numerical simulation methods that are based on particle system dynamics. Several distinct classes of such methods are evolved, including molecular dynamics, dynamics of complex fluids, smoothed particle hydrodynamics [1-6]. Efficient N-body algorithms, integration schemes, and parallel software implementations are already developed [7-9], including algorithms that are suitable for massively parallel hardware [10, 11]. However, during modeling the dispersions that are encountered in construction material science, there are some types forces (both pair forces between particles of fillers and aggregates and the forces that are due to steric conditions and processing technology) that can not to be taken into account by existing software packages. The example of complex pair force is the force caused by solvation shells. The particle with solvation shell can be modeled as two concentric spheres composed with rigid (impenetrable) core and viscous shell; such model is general enough to represent both microand macrostructure level of constructional composite. The viscous force can be estimated as a value proportional to cross section of the shells (outer spheres). Neither such estimation method nor the computational scheme that uses it is implemented in existing software. Because of the absence of ready to use software package that is suitable for the modeling of building materials, the decision was made to implement such software. Modeling Method The building materials are typical dispersions that are made of dispersion medium (water, liquid polymer etc.) and fine fillers. Structure formation of such materials is mostly determined by the surface forces that are originating between closely located particles of the filler. The surface forces can lead to the forming of clusters, which have significant influence both on the rheological properties of mixtures and the performance properties of the building materials. In many cases the motion law for particles of the fine filler can be written as: ( ) i i i i i i U k m −∇ = − − u r r & & & , N i , 1 = , (1) International Symposium on Mechanical Engineering and Material Science (ISMEMS 2016) Copyright © 2016, the Authors. Published by Atlantis Press. This is an open access article under the CC BY-NC license (http://creativecommons.org/licenses/by-nc/4.0/). Advances in Engineering Research, volume 93