Internal boundary conditions
If the pipeline cannot be considered as a continuous beam, as in case of articulated pipelines, the connection type between the separate pipe sections has to be specified.
Examples of articulated pipelines are (nodular) cast iron, (reinforced) concrete, plastic (PE, PVC) and glazed stoneware pipelines provided with whether or not anchored socket-spigot connections.
Other applications are articulation joints at the transition to rigid (building) structures and expansion joints or compensators in hot pipelines.
The non-tensile resistant articulation joint is modelled by two socket-spigot joints and the tensile resistant articulation joint is modelled by two ball hinges at a distance B of each other.
The bellows type of connection can be specified with stiffnesses in axial, transverse, torsional and rotational direction.
With Socket types the local X-axis is equal to the local X-axis of the adjacent element with the lower element number.
With Spigot types the local X-axis is equal to the local X-axis of the adjacent element with the higher element number.
For all other types (“Sleeve”, “Ball”, “Hinge”, “Tight” and “Bellows”) the local X-axis is perpendicular
to the bisector of the local X-axes of both adjacent elements.
InternalBoundary, last changed: 1/31/2020