The analysis of the stress state induced by the make up torque of threaded tapered connections is very important both for static and for fatigue resistance improvement of the connections. Make up torque induces a non uniform stress state; in the same way the axial load, induced by the make up torque, is distributed in a non uniform way along the sections of the coupled elements of the connections. The most important consequence is the overload at the first threads engaged, that has to be summed to the stress concentration in the core section due to the notch effect.Aim of this paper is to analyse the stress and strain fields induced by make up torque in threaded tapered connections; in particular the purpose is to investigate the effects induced by the application of an over-torque before putting in service the connections (stress relief due to over-torque before nominal make up torque application). The evaluation of the local stress state and of stress relief, with a good level of precision, was performed by using finite elements models with the aim of evaluating the percentage of load carried by each thread after the application of the make up torque and further axial tensile or compressive loads. Numerical results confirmed the favourable thread load distribution induced by over-load. Experimental tests, carried out on full-scale connections, that enable the joining of pipes used in the oil and gas industry, confirmed the numerical results.

(2004). Effects of over-torque on stress relief of conical threaded connections [journal article - articolo]. In JOURNAL OF MECHANICAL DESIGN. Retrieved from http://hdl.handle.net/10446/20291

Effects of over-torque on stress relief of conical threaded connections

Baragetti, Sergio;
2004-01-01

Abstract

The analysis of the stress state induced by the make up torque of threaded tapered connections is very important both for static and for fatigue resistance improvement of the connections. Make up torque induces a non uniform stress state; in the same way the axial load, induced by the make up torque, is distributed in a non uniform way along the sections of the coupled elements of the connections. The most important consequence is the overload at the first threads engaged, that has to be summed to the stress concentration in the core section due to the notch effect.Aim of this paper is to analyse the stress and strain fields induced by make up torque in threaded tapered connections; in particular the purpose is to investigate the effects induced by the application of an over-torque before putting in service the connections (stress relief due to over-torque before nominal make up torque application). The evaluation of the local stress state and of stress relief, with a good level of precision, was performed by using finite elements models with the aim of evaluating the percentage of load carried by each thread after the application of the make up torque and further axial tensile or compressive loads. Numerical results confirmed the favourable thread load distribution induced by over-load. Experimental tests, carried out on full-scale connections, that enable the joining of pipes used in the oil and gas industry, confirmed the numerical results.
articolo
2004
Baragetti, Sergio; Terranova, Angelo
(2004). Effects of over-torque on stress relief of conical threaded connections [journal article - articolo]. In JOURNAL OF MECHANICAL DESIGN. Retrieved from http://hdl.handle.net/10446/20291
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/10446/20291
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