*heading
 test vuel - 3d uncoupled springs; needs: vuel_springs_3d.f
 period = 2*Pi*sqrt(dMass/dStiff)=0.16453 (Analytical)
 period obtained using connector element (abq_connector_freevibx.inp)=0.1645833
 period obtained using vuel (this input deck)=0.164503 (measured from 12 cycles)
*parameter
**
** translation properties
dMass  = 7214.5
dStiff = 1.0521e7
dDamp  = 0.0
**rotational properties
dRotStiff_xx = 1000.0
dRotStiff_yy = 1000.0
dRotStiff_zz = 2000.0
dRotDamp = 0.0
**
ri_xx = 0.1
ri_yy = 0.2
ri_zz = 0.3
ri_xy = 0.04
ri_yz = 0.05
ri_xz = 0.06
**------------------------------------------------
*preprint,echo=yes,model=yes,hist=yes
*NODE,NSET=PR
101,
102,2.
*nset, nset=qa_test_leftnode
 101,
*nset, nset=qa_test_rightnode
 102,
**------------------------------------------------
*USER ELEMENT,NODES=2,TYPE=VU1001,PROPERTIES=14,COORDINATES=3,VARIABLES=18
1,2,3,4,5,6           
*ELEMENT,TYPE=VU1001,elset=utruss
1001 , 101,102
*UEL PROPERTY,ELSET=UTRUSS
<dStiff>, <dDamp>, <dMass>,   <dRotStiff_xx>,<dRotStiff_yy>, <dRotStiff_zz>,<dRotDamp>,0.0
<ri_xx>, <ri_yy>, <ri_zz>, <ri_xy>, <ri_yz>, <ri_xz>
**------------------------------------------------
*BOUNDARY
101,1,6
102,2,6
*initial conditions, type=velocity
102, 1, 1.0
**------------------------------------------------
*step, nlgeom=yes
*dynamic,explicit,elem, scale factor=0.1
,2.0
***variable mass scaling, elset=utruss,
** type=uniform,frequency=2,dt=1.e-2
*bulk viscosity
0.0,0.0
*output,field,var=preselect,num=1
*output, history, freq=1
*node output,nset=PR
u,v,a,rf
*node output, nset=qa_test_leftnode
 RF,
*node output, nset=qa_test_rightnode
 U, V, A
*energy output
*END STEP
**------------------------------------------------