Considering that the shapes of particles have an important impact on the mechanical properties of the coarse aggregate

this paper proposes a new method for characterizing particle shapes. The method randomly selects a series of points on ellipse; then those points are connected to form polygon particles. The new method can represent more types of particle shapes than old method that access points on the circle

applies more broadly

can characterize the narrow flat particles. In addition

a new algorithm of particle delivery is proposed

which is to reduce the particle; then the reduced particles are put to the given area randomly. After the particle was meshed by triangular element

the reduced particles was enlarge to the original size. Afterwards

using finite combined finite-discrete element method(FEM/DEM) to calculating equilibrium state

a sample that meet given void ratio was generated. Then the particle generation algorithm above and FEM/DEM was combined

the FEM/DEM method is applied to coarse aggregate numerical simulation

the analysis shows

FEM/DEM is a great way to study the mechanical properties of coarse aggregate. The complex particle shape can also be modeling simply

because the particles was meshed into the triangle finite element

complex contact judgments and the contact force calculation can be transformed into a standard uniform contact judgments and contact force calculations between triangles

all calculations can be standardization and unification. At the same time

particles can be deformed

the concept of stress and strain that belong to the continuum mechanics was still retains

rather than PFC which stress and strain of a point was expressed indirectly by the measuring circle. Finally

by confined compression test numerical simulations of coarse aggregate show enormous potential of the proposed set of solutions in the simulation coarse aggregate.