Numerical simulation of Rotary Shouldered Threaded Connections under Combined Static Loading

Rotary Shouldered Connections (RSC) are vital components of the extraction equipment in the oil and gas industry. Although the standards propose practical rules for drawing working limits for these mechanical parts, the combination of make-up torque and tensile and compressive external loads often produces damage and breakages during drilling operations. In order to model the complex non-linear effects, a FEM model of the threaded pinbox shouldered connections is developed, describing friction contact and including plastic effects by a linear elastic – perfectly plastic model. Due to the complexity of the geometry, 2D axialsymmetric eight-node biquadratic elements are adopted. The effects of traction on the pin and compression on the box generated by the make-up torque are simulated introducing a suitable heat load, by considering a virtual orthotropic coefficient of thermal expansion. Results are validated against experimental data.