2. Pipeline Configuration [GENCONF]

Compose pipeline configuration

General description:

Through this design function the spatial shape of the 3D pipe structure is composed by means of a defined spatial polygon. The defined pipe element division over the pipeline axis is elaborated. If provided, vertical profile data with respect to pipeline axis are also elaborated.

Function description:

The spatial polygon is defined in the input table POLYDIF with its start point defined in the input table ORIGIN. The function locates the specified bends in the polygon and generates a pipe-node distribution over the pipeline axis according to the pipe- element length specification provided in input table POLYDIF.

Apart from the NODES-list with the coordinates of the nodes and the ELEMENTS-list with the element distribution over the pipeline axis, the data-sets contained in the output data tables SHAPEP, SHAPEB, LENGTH and PROFILE resulting from the function, enable the designer to evaluate the specified pipeline configuration. In order to be able to specify a more refined element distribution at the adjacent stretches at bends, the element distribution at the bends can be extended by a number of elements specified in column EXT of table POLYDIF. It is noted that both the element distribution in bends and the element length measurement is done along the bend arc. The program assigns the bend polygon ident to the tangent points with the addition of 's' and 'e'.

Pipe branches may be modeled by specifying in table CONNECT which points of the configuration are connected to each other. Such connections are assumed to be rigid. The connections can be defined as tees with flexibility and stress intensification factors according to NEN-EN13480-3, with application of some notes from ASME B31.8 appendix E-1, that are lacking in the NEN code. Only in case of analysis type 'General' or 'NEN 3650-2' the NEN factors are taken into account. Analysis type 'ASME B31.8' still uses the factors from the ASME code. Then connected points have to be polygon points. Several tee types are available, see description of tables TEECONF and TEESPEC. The flexibility and stress intensification factors are calculated by the program and taken into account when determining pipeline displacements and stresses. A PIPE element adjacent to a TEE element must be in direct line with that TEE element. The 3 ends of a tee are always identified by nodes. Moreover the program assigns the TEE-ident to the ends with the addition of 's', 'e' and 'b'. When generating the nodes the run or branch element length of the tee (plus possibly the added length of extension elements) is subtracted from the polygon length and the remaining length is divided into equal distances in accordance with the specified maximum element length.

Steel in steel sections can be modeled by specifying the start and end idents of both the inner and outer pipe sections in table SISSECT. Fixed connects in a steel in steel section should be defined in table CONNECT. Partially restrained connections (e.g. Rollers) can be specified in table SISPRC. The ‘roller’ locations are assigned on the inner pipeline section and subsequently related to the nearest location (perpendicular to the outer pipeline section axis) on the outer pipeline section. The location on the outer pipeline is defined by the shortest intersection line between ‘roller’ location and outer pipeline section, perpendicular to the outer pipeline. As the roller connection is defined on the inner pipeline, the partially restrained connection is related to the LOCAL coordinate system of the outer pipeline.
Rollers can be seen as a special kind of connects: medium and casing tube can axially move independent of each other. This also counts for the rotations. Lateral the roller connections are rigid.

Although there are few requirements on the configuration of a steel in steel section (both pipes even do not have to be parallel) it is advised to define a section as it is built. A small number of rules apply to a Steel In Steel pipeline:

Rollers should only be defined on the inner pipe between the start and end of the inner pipe section. .
A roller should have an accompanying outer pipe element.
An outer pipe element should just have one roller
Weaks and joints are not allowed in a steel in steel section.
The inner pipe should fit in the outer pipe.

 

After design function 5 has finished the iteration process, a check on physical impossibilities is performed. When at any place the inner pipe wall passes through the outer pipe wall a function error is generated.

By means of table GROUPS elements can be divided into different groups, for instance elements with different wall thicknesses.

Moreover the program generates automatically the following groups if present:

 

(not user-grouped)

(only generated if any user-defined group is present)

All physical elements

(all elements except weak and joint elements)

Pipe elements

Bend + elastic elements

Bend elements

Elastic elements

SIS (all)

SIS (inner pipe)

SIS (outer pipe)

SIS section A (inner)

(not generated if only one SiS section is present)

SIS section A (outer)

(not generated if only one SiS section is present)

SIS section B (inner)

(generated also as C..Z for 3 to 26 sections)

SIS section B (outer)

(generated also as C..Z for 3 to 26 sections)

Tees (all)

Tees (Run)

Tees (Branch)

Supports (all)

Supports (Pipes)

Supports (Bends)

Supports (Elastic)

Connections

Joint elements ¹

"Weak" elements ¹

Elements with slack

(not reported in the "Element/node groups" table)

"Infinite" boundaries

(not reported in the "Element/node groups" table)

All elements

 

¹ Weak and Joint elements are no physical elements.

By selecting an element group in output tables with an ELEM or NODE column only these elements are shown, printed and plotted.

An articulated pipeline can be modeled by specifying one or more joints through table PIPES. A joint is defined as an element with 2 nodes with the same coordinates, so having zero length. A defined bend in table POLYDIF can be replaced by an articulated pipeline. The first joint should be located before or at the tangent point, the last joint at or after the tangent point. The corresponding degrees of freedom of the nodes can obtain different values depending on the characteristics of the joint. The element type in table ELEMNTS is JOINT. Several joint types are available, see tables JOINTS and JNTSPRS in Design Function 3.3. Examples are hinges, socket-spigot connections and bellows units.

Groups of spring supports having the same characteristics can be specified easily in input table SUPPORT. If such a support is specified with a length and a support angle, two support elements will be generated each with a length equal to half the specified support length.

Output table IDENTS contains all the idents both specified in tables ORIGIN, POLYDIF and ADIDENT, and generated by the program at the tangent points of the bends and the end points of Tees.


H2003, last changed: 14/09/2016

See also:

Input data table overview

Output data table overview

Design function errors, warnings and messages