Simulation of casing connection and optimization on end pitch of coupling

An axial symmetric FEM model is established for API 8 tooth round thread casing connection. The contact behavior and stress-strain distribution in the connection area are analyzed when the connection is screwed down by machine, especially under different end pitch values. Through investigating the effect of end pitch, it is proposed that the best pitch of the hoop should be 50-55°. This result has been successfully used in practice.