Influence of geometrical parameters of the drilling pipe on fatigue fracture

In exploitation the drilling pipes there are destructions connected with fatigue fracture in the transition zone between body of a pipe and landing part. There is a stress concentration as a result of change of its thickness. The analysis of form of the transition zone was carried out by finite element method. The received results show that the factor of stress concentration in a place of transition of pipe body in landing part depends on geometrical parameters of transition zone.