ABSTRACT

DEM analysis, we can isolate the effect of crushability more easily than the ordinary test carried with real granular material.

2 MODELING OF PARTICLE AND INDEX FOR PARTICLE BREAKAGE

We used the numerical model as mentioned bellow to simulate particle breakage. This is a similar method to the one introduced by Cheng et al. (2004). Figure 1 shows the particle model used. The “element particle”, which has the same diameter and was connected to each other by the intergranular adhesive force, was put inside the “original particle” to make agglomerate.The “agglomerate” consists of the aggregate of the element particles. We changed each of the original particles to the agglomerate. When the intergranular force overcomes the intergranular adhesive force acting between

Element particle

Original particle

Agglomerate (3 columns)

the element particles, the intergranular adhesive force disappear and the element particle become free from the agglomerate. Because we used the same size of diameter of element particle, when it becomes free form the bale particle, the detached particle has the same size. This state is similar to the behavior of particle breakage observed in test results for real granular materials. (Karube et al. 1999)

We applied the same value of the intergranular adhesive force for the perpendicular and the horizontal direction to the contact plane respectively at the same contact point between the element particles. But the magnitudes of the intergranular adhesive force are different at each contact point, and they distributes in normal distribution whose standard deviation is 1.0 × 103 (N), and averages are 5.0 × 104 (N), 5.0 × 105 (N) and 5.0 × 106 (N). These values are decided in trials and errors from preliminary simulation results of biaxial test, in which the crushing process is well simulated.