*HEADING
 CONN_STD_FREE_AXI: free vibration of spring-mass-dashpot  [CONN2D2]
 Damped free vibration:
  u(t) = e^{-w_n*t} u_0 ( xi/sqrt(1-xi*xi) sin(w_d*t) + cos(w_d*t) )
  u(0) = u_0 = 1.0, v(0) = 0.0
  w_n = sqrt(k/m)           = 2.0
  xi  = c/(2 m w_n)         = 5/48
  w_d = w_n sqrt(1 - xi*xi) = 1.98912
*************************************************
** create a rigid base for the connector elements
*************************************************
*NODE,NSET=PLATE
 101,  0.,  0.
 107,  0.,  6.
 701,  6.,  0.
 707,  6.,  6.
*NGEN,NSET=E1
 101,107,1
*NGEN,NSET=E2
 107,707,100
*NGEN,NSET=E3
 701,707,1
*NGEN,NSET=E4
 101,701,100
*NGEN,NSET=INTERIOR
 201,207,1
 301,307,1
 401,407,1
 501,507,1
 601,607,1
*NSET, NSET=NPLATE
 E1, E2, E3, E4, INTERIOR
*ELEMENT,TYPE=CAX4R,ELSET=PLATE
 101, 101,201,202,102
*ELGEN,ELSET=PLATE
 101,6,1,1,6,100,100
*SOLID SECTION,ELSET=PLATE,MATERIAL=MAT
*MATERIAL,NAME=MAT
*ELASTIC
 1.0,0.0
*NODE,NSET=REF
 1000, 0.,0.
*RIGID BODY, REFNODE=1000, ELSET=PLATE, TIE=NPLATE
*************************************************
*NODE,NSET=TOP
 1303,  2., 2.
 1305,  2., 4.
 1307,  2., 6.
 1503,  4., 2.
 1703,  6., 2.
 1705,  6., 4.
*******************************************
** put mass and rotary inertia at top nodes
*******************************************
*ELEMENT, TYPE=MASS, ELSET=MASS
 1011,1303
 1012,1305
 1013,1307
 1021,1503
 1031,1703
 1032,1705
*MASS, ELSET=MASS
 12.0
*ELEMENT, TYPE=ROTARYI, ELSET=ROTI
 2011,1303
 2012,1305
 2013,1307
 2021,1503
 2031,1703
 2032,1705
*ROTARY INERTIA, ELSET=ROTI
 120.0, 120.0, 120.0
********************************
** define the connector elements
********************************
*ELEMENT, TYPE=CONN2D2, ELSET=AX
 11, 202, 1303
*ELEMENT, TYPE=CONN2D2, ELSET=CAR
 12, 204, 1305
*ELEMENT, TYPE=CONN2D2, ELSET=SLT
 13, 206, 1307
*ELEMENT, TYPE=CONN2D2, ELSET=ROT
 21, 402, 1503
*ELEMENT, TYPE=CONN2D2, ELSET=CAR-ROT
 31, 602, 1703
*ELEMENT, TYPE=CONN2D2, ELSET=SLT-ALN
 32, 604, 1705
*ELSET,ELSET=CONNALL
 AX, CAR, SLT, ROT, CAR-ROT, SLT-ALN
*ORIENTATION, NAME=LDIRECTION
** orientation along node line
 1.,1.,0., -1.,1.,0.
*****
*CONNECTOR SECTION, ELSET=AX, BEHAVIOR=CB_AX
 AXIAL,
*CONNECTOR BEHAVIOR, NAME=CB_AX
*CONNECTOR ELASTICITY, COMPONENT=1
 48.0,
*CONNECTOR DAMPING, COMPONENT=1
 5.0,
*****
*CONNECTOR SECTION, ELSET=CAR, BEHAVIOR=CB_CAR
 CARTESIAN,
 LDIRECTION,
*CONNECTOR BEHAVIOR, NAME=CB_CAR
*CONNECTOR ELASTICITY, COMPONENT=1
 48.0,
*CONNECTOR DAMPING, COMPONENT=1
 5.0,
*CONNECTOR ELASTICITY, COMPONENT=2
 48.0,
*CONNECTOR DAMPING, COMPONENT=2
 5.0,
*****
*CONNECTOR SECTION, ELSET=SLT, BEHAVIOR=CB_SLT
 SLOT,
 LDIRECTION,
*CONNECTOR BEHAVIOR, NAME=CB_SLT
*CONNECTOR ELASTICITY, COMPONENT=1
 48.0,
*CONNECTOR DAMPING, COMPONENT=1
 5.0,
*****
*CONNECTOR SECTION, ELSET=ROT, BEHAVIOR=CB_ROT
 ROTATION,
 LDIRECTION,
*CONNECTOR BEHAVIOR, NAME=CB_ROT
*CONNECTOR ELASTICITY, COMPONENT=6
 480.0,
*CONNECTOR DAMPING, COMPONENT=6
 50.0,
*****
*CONNECTOR SECTION, ELSET=CAR-ROT, BEHAVIOR=CB_CAR-ROT
 CARTESIAN,ROTATION
 LDIRECTION,
*CONNECTOR BEHAVIOR, NAME=CB_CAR-ROT
*CONNECTOR ELASTICITY, COMPONENT=1
 48.0,
*CONNECTOR DAMPING, COMPONENT=1
 5.0,
*CONNECTOR ELASTICITY, COMPONENT=2
 48.0,
*CONNECTOR DAMPING, COMPONENT=2
 5.0,
*CONNECTOR ELASTICITY, COMPONENT=6
 480.0,
*CONNECTOR DAMPING, COMPONENT=6
 50.0,
*****
*CONNECTOR SECTION, ELSET=SLT-ALN, BEHAVIOR=CB_SLT
 SLOT,ALIGN
 LDIRECTION,
*****
*BOUNDARY
 REF, 1,6
 TOP, 3,5
1303,2,2
*****
*ELSET,ELSET=D10
** initial displacement in local (1,0) direction.
** AXIAL, SLOT, SLT-ALN
 11, 13, 32 
*ELSET,ELSET=D11
** initial displacement in local (1,1) direction.
** CARTESIAN, CAR-ROT
 12, 31
*ELSET,ELSET=R001
** initial angular displacement in local (0,0,1) direction.
** ROTATION, CAR-ROT
 21, 31
************************************
*STEP, PERT
 This step should produce the same results as the linear
 static step which follows
*STATIC
*CONNECTOR MOTION
 D10,1, 0.1
 D11,1, 0.1
 D11,2, 0.1
 R001,6, 0.1
*EL FILE, ELSET=CONNALL
 CP,CU,CV
*OUTPUT,HISTORY, FREQ=1
*ELEMENT OUTPUT, ELSET=CONNALL
 CP,CU,CV
*NODE OUTPUT, NSET=TOP
 U,V,A
*END STEP
************************************
*STEP, NLGEOM=NO
 Every dof should give the same answer.
*STATIC
*CONNECTOR MOTION
 D10,1, 0.1
 D11,1, 0.1
 D11,2, 0.1
 R001,6, 0.1
*EL FILE, ELSET=CONNALL
 CP,CU,CV
*OUTPUT,HISTORY, FREQ=1
*ELEMENT OUTPUT, ELSET=CONNALL
 CP,CU,CV
*NODE OUTPUT, NSET=TOP
 U,V,A
*END STEP
************************************
*STEP, NLGEOM=NO, INC=200
 Damped free vibration.
*DYNAMIC, ALPHA=0.0, NOHAF
 0.075, 8.0
*CONNECTOR MOTION, OP=NEW
*FILE FORMAT, ZERO INC
*EL FILE, ELSET=CONNALL, FREQ=10
 CP,CU,CV
*OUTPUT,HISTORY, FREQ=1
*ELEMENT OUTPUT, ELSET=CONNALL
 CP,CU,CV
*NODE OUTPUT, NSET=TOP
 U,V,A
*END STEP