Adjusting crane boom angle during an upending operation

Hi there, 

I was doing a 2 block upending analysis for the jacket. Noted that i can vary the main hook and aux hook Hight at each event by by setting an instate for the jacket.

But i have a stage where i need  to increase boom angle by 10 Deg for better ground Clarence. 

So i  need to know how this can be during the upending processes.

have seen the C_POS macros used in the crane vessels but how can this be used inside the upending files.

Tried defining the crane boom as separate body and move in the command file (But i couldn't keep the crane boom in a fixed position for cases where boom should be fixed even after ignoring all DOF) 

Thanks in advance 

Cheers 

Rohith

 

Parents
  • Hi Rohith,

    This is easy to do using the MEDIT menu. Since I don't have your files, I will try to explain using a hypothetical situation shown below.

    The block of code to change the boom angle in the MEDIT menu is provided below. 

    $Let's assume you have a jacket body with 4 points where the slings are connected, labeled as *j1, *j2, *j3, and *j4.
    $Let's assume in the barge model file you have defined the crane pedestal point as *cpd in the barge.dat file. The hook (*mhk) point changes depending on the boom angle; therefore, we will define it in the MEDIT menu in the CIF file.
    $In the .cif file, we define the crane (as a beam for display purposes) and the boom tip point (*mhk).
    $
    &title Step 1 Boom Angle 60 deg 
    &describe body barge 
    medit 
        *mhk x1 y1 z1                                $x1 y1 and z1 are the coordiante of boomtip at 60 degree boom angle in barge coordiante system
        ~tube tube 508 0.1 
        beam ~tube *mhk *cpd                         $this crane is for visual representation. 
        $ Main Slings
        ~MB  sling MSD -len L1 -emod %E%             $MSD is main sling diameter, L1 is main sling lenght. 
        ~MS_1  sling SD -length LS1 -emodulus %E      $ SD is the sling diameter. E is modulus of elasticity. LS1 -- LS4 are the jacket sling lenghts. 
        ~MS_2  sling SD -length LS2 -emodulus %E
        ~MS_3  sling SD -length LS3 -emodulus %E
        ~MS_4  sling SD -length LS4 -emodulus %E
        $
        connector MBLOCK  ~mb *mhk
        connector MS_1  ~MS_1 *J1
        connector MS_2  ~MS_2 *J2
        connector MS_3  ~MS_3 *J3
        connector MS_4  ~MS_4 *J4
        assembly t-h_definition MBLOCK MS_1 MS_2 MS_3 MS_4 -initial
    end_medit
    $
    &equi -maxit 1000 
    &event 1
    &status connector -both 
    &status tip-hook -both 
    $
    &title Step 2 Boom Angle 80 deg 
    medit 
        *mhk x2 y2 z2                                $x2 y2 and z2 are the coordiante of boomtip at 80 degree boom angle in barge coordiante system 
        ~tube tube 508 0.1 
        beam ~tube *mhk *cpd                         $this crane is for visual representation. 
        $ Main Slings
        ~MB  sling 418 -len L1 -emod %E%  
        ~MS_1  sling SD -length LS1 -emodulus %E
        ~MS_2  sling SD -length LS2 -emodulus %E
        ~MS_3  sling SD -length LS3 -emodulus %E
        ~MS_4  sling SD -length LS4 -emodulus %E
        $
        connector MBLOCK  ~mb *mhk
        connector MS_1  ~MS_1 *J1
        connector MS_2  ~MS_2 *J2
        connector MS_3  ~MS_3 *J3
        connector MS_4  ~MS_4 *J4
        assembly t-h_definition MBLOCK MS_1 MS_2 MS_3 MS_4 -initial
    end_medit
    $
    &equi -maxit 1000 
    &event 2
    &status connector -both 
    &status tip-hook -both 
    $

    Please let me know if this is clear. In case you face any issues please upload your files here or you can as well send me at rahul.kanotra@inventocean.com

    Regards, 

    Rahul Kanotra 

  • Hi Rahul, 

    Thanks for the response.

    But  I did it in a different way, Please let me know if its right.

    I will send you the files personally 

    Thanks and regards 

    Rohith 

  • Hi Rohith,

    Sure please send me your files at rahul.kanotra@inventocean.com and some explanation about the files. I will have a look at get back as soon.

    Thanks

    Rahul

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