Stress and Displacements Analysis for Drilling Mast Elements Made of Rectangular Pipe under the Action of the Wind as a Hurricane

摘要

According to API 4F, SR EN ISO 14693:2004, the action of wind as a hurricane, with a speed of 120 km/h, represents a special load the drilling masts, which are a part of the drilling rigs, are submitted to. By their construction, the masts are multiple statically indetermined structures, made of many welded ends beams, and are designed as a component of the hoisting system, having some main purposes as supporting devices as the crown block at the top, the crane, the rotary swivel etc and providing support for the drill pipes to be stacked vertically during the round trips operations. In the present paper was analyzed, from this point of view, a drilling mast prototype made of rectangular pipes, rated for a maximum hook load of 300 kN. The authors calculated the wind pressures, in accordance with the formulae specified in the standards, and introduced this special loading as a distributed load, firstly on the transversal direction of the mast and then on the longitudinal direction, with respect to the spatial reference system attached to the analyzed mast. Using the Finite Element Method, the nodes displacements and mast's elements stress were determined. The most important obtained values of the displacements and stress were graphically shown and commented and, also, interesting conclusions are presented concerning the drilling mast resistance in specific conditions that occur in case of the wind action as a hurricane, as a premiere contribution for this new design of mast.