(51b) MODELING the MECHANICS of Drilling Bit

The mechanics of rock drilling is complex. This complexity hinders the development of modeling tool that can serve as a reliable predicative tool. By reliable tool we mean that the cutting forces and fragmental process can be reasonably estimated. From a modeling perspective, advancing a drilling bit constitutes a sequence of challenging problems: A contact problem first arises as a drilling bit interacts with a target rock. This is followed by the task of determining when and if the rock would fail. If the rock does fail, a modeler is further faced with the problem of how to initiate the fragmentation process. Subsequently, this sequence of problems repeats itself as the drilling progresses. This study adopted a ground up modeling approach by starting first with the development of a single cutter model. Both the finite element method and the discrete element methods were employed. After extensive work on both linear and circular cutting modeling, a preliminary full drilling bit was built. These models are still being tested, and some of the results will be presented.