INTERNAL UPSET TAPER DESIGN OF A DRILL PIPE BASED ON STRESS CONCENTRATION ANALYSIS

On the basis of investigation on the influence of internal upset transition geometry on thestress concentration of a drill pipe, basic design requirements for a drill pipe with low stress concentration were proposed. Full size fatigue tests werecarried out to verify that analytically designed upsettaper geometry has a good performance. The workin this paper provides important basis for improvinginternal upset taper design of a drill pipe.