Parametric finite element model for large scale tension tests on flawed pipeline girth welds

Abstract

The structural response of a pipe with a flawed girth weld, subjected to global plastic deformation is influenced by a large number of geometrical and material properties. Finite element models that aim to simulate this need to include all relevant influence factors, which causes high challenges in the creation of such models. In search for a high degree of flexibility, automation and ease of use, the authors have developed a parametric script that creates geometries for two common pipeline girth weld tension tests: the curved wide plate test and the full scale pressurized pipe tension test. The developed model allows to modify pipe geometry, test specimen geometry, flaw position (weld metal centre or heat-affected zone), flaw size, weld misalignment, pipe thickness variations, weld fusion line profile, and weld cap profile. The desired geometry is obtained by a coordinate transformation scheme that starts from a flat plate with a simplified weld geometry. A deliberate partitioning strategy is applied to obtain flexibility in the flaw location and full independence between a fine flaw mesh and a coarse body mesh. This article describes the approach, structure and governing equations of the model. An example geometry is discussed to illustrate the various possibilities. The proposed model provides inspiration for all who seek to develop parametric finite element models with a similar flexibility and ease of use.