*elset,elset=fuel-tank1
*surface,name=fuel-tank1
fuel-tank1,SPOS
*COUPLING,REF NODE=9190031,SURFACE=fuel-tank1,CONSTRAINT NAME=fuel-tank1
*DISTRIBUTING
**--------------------------------------
*elset,elset=fuel-tank2
*surface,name=fuel-tank2
fuel-tank2,SPOS
*COUPLING,REF NODE=9190032,SURFACE=fuel-tank2,CONSTRAINT NAME=fuel-tank2
*DISTRIBUTING
**--------------------------------------
*elset,elset=fuel-tank3
*surface,name=fuel-tank3
fuel-tank3,SPOS
*COUPLING,REF NODE=9190033,SURFACE=fuel-tank3,CONSTRAINT NAME=fuel-tank3
*DISTRIBUTING
**--------------------------------------
*elset,elset=fuel-tank4
*surface,name=fuel-tank4
fuel-tank4,SPOS
*COUPLING,REF NODE=9190034,SURFACE=fuel-tank4,CONSTRAINT NAME=fuel-tank4
*DISTRIBUTING
**--------------------------------------
** add dummy mass/rotary inertia to coupling ref nodes
*ELEMENT, TYPE=MASS, ELSET=fuel_tank_mass
*MASS, ELSET=fuel_tank_mass
<small_mass>,
*ELEMENT, TYPE=ROTARYI, ELSET=fuel_tank_rotary
*ROTARY INERTIA, ELSET=fuel_tank_rotary
<small_rota>,<small_rota>,<small_rota>
**---------------------------------------------------------
*nset,nset=retained_fuel_tank,unsorted
*nset,nset=retained_all
retained_fuel_tank,
**