CONTACT NONLINEAR FINITE ELEMENT ANALYSIS OF DRILL RODS IN 3D CURVED BOREHOLES

A new contact model is proposed to simulate the interaction between drill rods and 3d curved boreholes in nonlinear finite element analysis. The proposed model restricts normal rod deformations inside the gaps and vanishes cross-section angles around the binormal axis of the deformed rod centerline. Based on the new contact model, finite element analysis scheme of drill rods in contact with curved boreholes is given using Bernoulli spatial curved beam elements. Numerical results of an end-fixed beam in contact with continuum show good agreement with analytical solutions. The model can avoid the unstable phenomenon when the number of the elements changes. The results of the finite element analysis on a real curved borehole is given and discussed.