Jacket Generation

Jacket Generation

Hydrostatics, Stability, and Ballasting

Seakeeping

Jacket/Deck Installation

Mooring

Using Our Tools

This is an example of the use of the macro JKT_GEN which is supplied in the tools directory. This macro generates the majority of the model for 8 pile jackets.

Most of our examples contain a common set of "beginning" commands as well as a common "ending" command. Click here to get documentation for these commands. They will not be discussed directly. The files which are discussed here are:

This macro generates a jacket model with just a handful of parameters. The macro is used in the data file, and the command file simply generates reports and plots of the model. Both of these files are discussed.

The Command File:

The command file for this sample is meant to generate summary reports and plots of the jacket generated with the macro JKT_GEN.

$
$*********************************************      write summary
$
&SUMMARY
   GEOM
END
&STATUS FORCE

The Summary menu is entered via the command &SUMMARY. The command GEOM is an internal macro. This command generates all the reports necessary to fully document the geometric properties of the jacket model. The reports generated are:

class dimensions
material and redesign properties
nodal summary for part jacket
point summary for part jacket
point scf summary
joint property summary
beam properties for part jacket
beam section data for part jacket
category summary for part jacket

The next block of commands generate pictures of the jacket.

$
$*********************************************      plots
$
&PLTMODE STRUCTURE
   PICTURE SIDE
   PICTURE TOP
   PICTURE FRONT
   PICTURE ISO

We enter the MOSES Illustrate menu with the command PLTMODE STRUCTURE command. Four pictures, a side view, a top view, a front view, and an isometric view are generated with the four command lines begining with the command PICTURE.

That concludes the discussion of the command file. The discussion of the data file follows.

The Data File:

Before we can use the macro JKT_GEN we have to tell the program that we want to use it. This is done in the following.

USE_MAC JKT_GEN

The command USE_MAC is an internal macro. The program will search for the specified macro starting with the current working directory and including the tools directory among others. The macro JKT_GEN is located in the tools directory along with documentation.

Before we can use the macro JKT_GEN we need to define the parameters.

&SET WPOINT =  15
&SET TOPELE =  12
&SET WDEPTH = 275
&SET WIDTH  =  45
&SET XODIM  =  40
&SET XIDIM  =  45
&SET BATTER =  &NUMBER(REAL 1/8)

The variables set here and the parameters needed. The following table is a short description of how each variable is used.

WPOINT is the vertical distance between the top of the jacket and mean water level
TOPELE is the top elevation
WDEPTH is the water depth
WIDTH is the width of the jacket
XODIM is the longitudinal spacing of the outer legs
XIDIM is the longitudinal spacing of the inner legs
BATTER is the batter

Having set the parameters we immediately use the water depth variable to set the water depth in the following command.

&PARAMETER -DEPTH %WDEPTH%

The water depth is the only parameter that needs to be set when defining a jacket. If the water depth is not set then it is possible that the resulting jacket will not sit on the sea floor.

Jacket generation begins with the PARBRA which takes as input some of the variables we defined earlier.

PARBRA 4 %TOPELE% -%WDEPTH% %WIDTH% %BATTER% -WPOINT %WPOINT%

The macro PARBRA determines the PARallel BRAcing elevations. The result of the PARBRA macro is the variable ELEV which is used in the next macros JKT_NODE and JKT_ELEM.

&DESCRIBE BODY JACKET JACKET
JKT_NODE %ELEV% -BATTER %BATTER% -WPOINT %WPOINT% \
               -YDIM %WIDTH% -XDIM %XODIM% %XIDIM%
JKT_ELEM %ELEV% -HORIZ B D D

The command &DESCRIBE tells the program we are begining the description of a body named JACKET. The macro JKT_NODE creates all the nodes and the macro JKT_ELEM creates all the elements needed in the jacket. The use of these two macros is discussed here.

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