Sammendrag
This work considers a predictive numerical modelling approach for fracture-propagation control in CO2-transport
pipelines, an area where current engineering tools do not work. Fluid-structure interaction model simulations are
compared with three published medium-scale crack-arrest experiments with CO2-rich mixtures. The fluid flow is
calculated by a one-dimensional homogeneous equilibrium model, and the thermodynamic properties of CO2 are
modelled using the Span–Wagner and the Peng–Robinson equation of state. The pipe material is represented by a
finite-element model taking into account large deformations and fracture propagation. Material data commonly found
in the literature for steel pipes in crack-arrest experiments is not sufficient to directly calibrate the material model
used here. A novel three-step calibration procedure is proposed to fill the information gap in the material data. The
resulting material model is based on J2 plasticity and a phenomenological ductile fracture criterion. It is shown
that the numerical model provides good predictions of the pressure along the pipe, the ductile fracture speed and a
conservative estimate of the final crack length. An approximately plane-strain stress state ahead of crack tip implies
that a fracture criterion accounting for a wide range of stress states is not necessary.
pipelines, an area where current engineering tools do not work. Fluid-structure interaction model simulations are
compared with three published medium-scale crack-arrest experiments with CO2-rich mixtures. The fluid flow is
calculated by a one-dimensional homogeneous equilibrium model, and the thermodynamic properties of CO2 are
modelled using the Span–Wagner and the Peng–Robinson equation of state. The pipe material is represented by a
finite-element model taking into account large deformations and fracture propagation. Material data commonly found
in the literature for steel pipes in crack-arrest experiments is not sufficient to directly calibrate the material model
used here. A novel three-step calibration procedure is proposed to fill the information gap in the material data. The
resulting material model is based on J2 plasticity and a phenomenological ductile fracture criterion. It is shown
that the numerical model provides good predictions of the pressure along the pipe, the ductile fracture speed and a
conservative estimate of the final crack length. An approximately plane-strain stress state ahead of crack tip implies
that a fracture criterion accounting for a wide range of stress states is not necessary.