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Perform a Roll Up
The rollup macro is a set of commands that will simulate a portion of a jacket being rolled by a set of cranes, and create a process in the program for this simulation. Once the process is created, load cases can be easily created for use in a structural analysis of the roll up. The macro will take the structure from horizontal (0 degrees) to vertical (90 degrees) in angle increments specified by the user. Maximum allowable crane loads can be specified, or a combination of crane loads and applied forces can be input. The applied forces simulate constant crane or winch loads. The syntax of the macro is shown below: 

 
   ROLLUP PART, ANGINC -OPTIONS
 
where the available options are:
 
   -SUPPORT, SN1, SN2, ......, SNn
 
   -AP_F,    AFN1, VF1, HF1, AC1, ......, AFNn, VFn, HFn, ACn
 
   -CRANE    CN1, ML1, CN2, ML2, ......, CNn, MLn
Here, PART is the part name of the structure to be analyzed, and ANGINC is the angle increment in degrees for the analysis. A process event will be generated at each angle of the roll up, from horizontal to vertical. Remember that a separate model of just the portion to be rolled up is not required, since elements can be deactivated by using the EL_ACTIV command under the MEDIT menu.

Nodes that are supported in the fabrication yard during the roll up are specified as SNn using the -SUPPORT option. The applied forces during the roll up are specified with the -AP_F option, where AFNn is the node name where the force is applied, VFn is the vertical force, HFn is the horizontal force, and ACn is the angle at the which the specified forces become active. The units for these forces are kips. These forces are not applied until the roll up angle is greater than ACn, after which the forces remain constant. This option allows one to simulate a crane that keeps a constant load during the roll up process. Also, the provision for both vertical and horizontal components of forces allows one to simulate a winch or crane that does not connect a lifting sling that is perpendicular to the jacket leg.

The -CRANE option is used to specify the maximum load a crane can apply during a roll up. The node where the load is applied is CNn, while the maximum load is MLn, in the same units noted above. The macro will iterate to find the required crane load at each roll up angle analyzed, such that the maximum allowable crane load is not exceeded and the desired angle is obtained.

At the conclusion of the macro, reports and plots of the simulation are generated. A structural analysis can now be performed, using the process generated by the macro, as shown below: 


 
     struct
        &loop ename (%elist%)
        lcase -proces P_%ename% %ename%
        &endloop
        &type Solving
        ssolve -nonlinear
     end
These results can then be post processed to obtain beam and joint code checks, restraint loads and joint displacements.