Simulation of wear on tricone drill bits using a bonded DEM model and geometry update

  • Svanberg, Andreas (Vastec Engineering AB & LTU)
  • Malmelöv, Andreas (Vastec Engineering AB)
  • Larsson, Simon (Luleå University of Technology)

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Wear during rock drilling is a major issue that leads to increased operational and maintenance costs in the mining industry. In this work we present a new method that uses a statistical bonded discrete element method (DEM) approach to model the rock [1]. Further, a FEM-model is used to model the tricone with corresponding drill bits. The wear is than accumulated due to wear law, calculating wear based on contact between FEM-DEM. In this study, an experimental rig is used to study the drilling and wear on drill bits in a controlled environment. Several drill bits, operational conditions, and materials are tested, and the wear is detected using a 3D-laser scanner. Subsequently, the experiment is set up numerically using LS-DYNA. An updated geometry approach is enhanced, where the geometry on the tricone drill bit is updated (due to the wear) after a certain interval to take the change in wear rate due to geometrical change into account. The wear from simulations is compared to experimental wear for the different scenarios. A sensitivity study is performed to relate DEM particle size and FE-mesh size to one another to speed up simulation times and still maintain enough accuracy on the wear. Preliminary results from this study, where an advanced rock breakage model and a wear geometry updating method together with well performed experiments have high potential in predicting the wear in a full scale tricone drill bit.