Neutral File Format - PDS - Help

Plant Design System (PDS) Stress Analysis Interface (PD_Stress)

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The neutral file produced by the PD_Stress Analysis Interface consists of eight sections of data. Each section of the file is composed of one or more records in the neutral file. Each record is composed of several fields. Fields in neutral file records are separated by commas.

Records in each section of the neutral file generally begin with a fixed keyword. When the neutral file is generated from a metric model file, the keywords add the prefix M (for example, NODE becomes MNODE).

Different sections of the file are related to each other through pointers. For example, temperatures and pressures stored at the segment level in a 3D model are generated in the file section where the record keyword is LOAD.

Data about each component in a network is put in a file section where records begin with PROP. A common text string (the pointer) in each of the record types associates a set of temperatures and pressures with a given component. These pointers keep the file reasonably compact.

The data contained in each section of the neutral file is outlined below:

Section 1

Set of comment records (with an exclamation mark in column one) listing all of the model files and line names used in the extraction. The date and time of the run is also included.

Section 2

Single record containing fields that identify the run. (Use of this record is not fully supported at this time.)

Section 3

Several records, each beginning with the keyword LOAD, which contain the temperatures and pressures of each piping segment in the piping network.

The second field contains a segment ID or pointer that is used to associate a set of temperatures and pressures with a given component. More than one LOAD record may be generated for a segment depending on how many temperature/pressure pairs you put on a single record.

Section 4

Records that begin with the keyword LSET. These records specify the temperature/pressure pair used from each segment when analyzing the line for different loading conditions (that is, deadweight, cold condition, hot condition and wind condition cases). The PD_Stress Analysis Interface puts values in these records based upon criteria you specified in the options file. (Refer to the Options File section for more information.)

Section 5

Records beginning with keyword CODE. A CODE record is generated for each unique value of the analysis code attribute stored in the piping segment entities. Each component has a pointer pointing back to one of these CODE records.

Section 6

Set of records for each component in the network. The first record of each set is an overall component record. It does not begin with a keyword. Instead, the first field consists of the component name obtained from the PDS to Stress Interface Symbol Map.

The second field contains a component ID or pointer that groups this record with the records that follow for the same component. This first record also contains network connectivity information through a list of node number corresponding to the component. Node numbering conventions for components are discussed later in this section.

Following this first record are a series of records that each begin with the keyword PROP. Each PROP record contains the component ID pointing back to the overall component record. Each of these records also has a form type identifying the data contained on the PROP record.

Data held in PROP records is of two types:

  • component type data. For example, a bent pipe PROP record might contain the bend radius and the bed angle.

  • connect point data. This data includes size and schedule. It also includes the segment pointer that associates each connect point with LOAD and LSET records.

Section 7

Records beginning with the keyword LNOD. These records are generated at equipment nozzles (indicating that the nozzle is an anchor_ and when data associated with a pipe support indicates that the support is acting as a node restraint. When a support acts only as a restraint, the component records are not generated for it. LNOD records define which directions and/or rotations are restrained at a node.

Section 8

Records beginning with the keyword NODE. These records hold the coordinate of each node in the network.


The overall file structure is outlined in general form below:

!
! Comments
!

LOAD, SEGID1, T1, P1, T2, P2, ...
LOAD, SEGID2, T1, P1, T2, P2, ...
.
.
.
LOAD, SEGIDn, T1, P1, T2, P2, ...

LSET, SEGID1, ...
LSET, SEGID2, ...
.
.
.
LSET, SEGIDn, ...

CODE, CODEID1, ...
CODE, CODEID2, ...
.
.
.
CODE, CODEIDn, ...

NAME1, COMPID1, CODEID1, ... N1, N2
PROP, NAME1, COMPID1, FORM1, ...
.
.
.
PROP, NAME1, COMPID1, FORMn, ... , SEGID1
PROP, NAME1, COMPID1, FORMm, ... , SEGID1
NAME2, COMPID2, CODEID1, ... N3, N4, N5
PROP, NAME2, COMPID2, FORM1, ...
.
.
.
PROP, NAME2, COMPID2, FORMn, ... , SEGID1
PROP, NAME2, COMPID2, FORMm, ... , SEGID2
PROP, NAME2, COMPID2, FORMo, ... , SEGID3
.
.
.
NAMEn, COMPIDn, CODEIDn, ... , Nm, Nm
PROP, NAMEn, COMPIDn, FORM1, ...
.
.
.
PROP, NAME2, COMPID2, FORMn, ... , SEGIDn
PROP, NAME2, COMPID2, FORMm, ... , SEGIDn

LNOD, Nn, ...
LNOD, Nm, ...

NODE, N1, x1, y1, z1
NODE, N2, x2, y2, z2,
.
.
.
NODE, Nn, xn, yn, zn

Within the form or skeleton outlined above, you can map attributes from the database into the neutral file by modifying the stress analysis options file.