Manoj Khanal

Oblique impact simulations of high strength agglomerates

Different type of particle compounds like concrete particles can be considered as a model material of high strength agglomerates. It is necessary to investigate and understand the fracture behaviour of these agglomerates in order to avoid breakage during storage, handling and transportation. The aim of the research is to examine the comminution behaviour of high strength agglomerates during oblique impact loadings. A two dimensional finite element analysis has been carried out to understand stress pattern distributions before crack initiation. Then a two dimensional discrete element method has been performed to study the fragmentation behaviour of the agglomerates. Concrete particles of B35 strength category have been chosen to represent the high strength agglomerates. The analysis is done with oblique impact loadings at different velocities from 7.7 m/s to 180 m/s. The stressing conditions comprise low flow rate transportation and handling to high speed impacts during fall down in bunker, stock piles, ship loading or stressing in crushers and mill operations. Particle size distributions and new surface generation have also been evaluated in the paper. It is shown that at higher velocities, particle size distributions are identical to each other regardless of the impact angle. Increasing impact velocity does not necessarily produce more new surfaces after a certain velocity limit.

Experiment and Simulation of Breakage of Particle Compounds under Compressive Loading

ABSTRACT Two-dimensional finite element (FE) compressive stress analyses were carried out on the particle compound material to understand the stress pattern distributions before cracking. FE analysis was followed by discrete element (DE) simulation. A study of the crack propagating mechanism in a particle was represented by a model material that typifies pellets of high-strength pressed agglomerate building materials. For this, concrete spheres of strength category B35 (compressive strength 35 N/mm2) were used. It was observed that the ring tensile stress is responsible for the crack initiation in the spherical particle compounds.

Comments on Numerical Simulation in Industrial Scale Comminution

Numerical simulations have the potential to be effective tools to interpret and investigate comminution mechanisms of mineral particles. Numerical techniques have been mostly used for single particle analysis or for the simulation of pilot-scale mineral processing equipment, within a steady-state processing environment. Due to insufficient fundamental understanding and computational limitations, it is a challenge to use these tools in downstream processing of particles. This article highlights the use of numerical tools in understanding comminution mechanisms of particles in industrial applications. Such understandings may assist in designing energy efficient comminution circuits. This article also considers the issues related to efficient comminution of particles. At present, there are three significant issues: representation of fine particle sizes (down to dust), heterogeneity of ores and the limitations of commonly accepted breakage models that need to be more fully understood in order to numerically simulate crushing and grinding circuits for industrial applications.

Crack Analysis in Single Plate Stressing of Particle Compounds

Particle compound material is the composition of different particles with inhomogeneous and non-uniform properties. Particle compound material is the most complicated engineering material whose properties vary according to the applications, method of manufacturing and ratio of its ingredients. The quasi-homogeneous materials like building materials and constituents of tablets, pellets etc are some of the examples of particle compounds.