Threaded-pipe connectors are common in oil, gas, and offshore piping applications. They join pipelines in environments where pipes are frequently coupled and decoupled. The connectors must withstand demanding operating conditions, as they are typically subjected to internal-pressure, axial-pullout, bending, and torsion loads.

It is arduous and time-consuming to begin a threaded-connection simulation with a 3-D model even when it is possible. Axisymmetric loads are significant and can be difficult to solve with contact, and a refined mesh is often necessary for detailed examination of a threaded connection.

Since the first few stages of loading (such as internal pressure and axial pullout) are axisymmetric in nature, and the loads causing nonaxisymmetric deformation (such as bending) occur later, you can conveniently use 2-D to 3-D analysis capability to perform a more convenient 2-D analysis in the early part of the with axisymmetric loads, followed by a general 3-D analysis later where nonaxisymetric loads are included.

A 2-D to 3-D analysis involves extruding a 2-D deformed mesh to a new 3-D mesh. The program updates the database as necessary, generates contact elements if needed, and transfers boundary conditions, loads, and nodal temperatures from the 2-D mesh to the extruded 3-D mesh. The program maps all solved variables (node and element solutions) to the new 3-D mesh and rebalances solutions for the 3-D model automatically. You can then continue the analysis on the 3-D model via a multiframe restart, applying nonaxisymmetric loading as desired.