*HEADING
 BUCKLING PROCEDURES - /STANDARD VERIFICATION, 2D CONNECTORS
**
*NODE
 1,0.0,0.0,
 11,0.0,10.0,
 100,-1.0,5.0,
*PARAMETER
 KAXIAL1=1.0E3
 KROT1=1.0E3
 U1=1.0E-3
 UR1=1.0E-3
 KAXIAL2=KAXIAL1/1000
 KROT2=KROT1/1000
 U2=100*U1
 UR2=100*UR1
 F1=KAXIAL1*U1
 M1=KROT1*UR1
 F2=F1+KAXIAL2*(U2-U1)
 M2=M1+KROT2*(UR2-UR1)
 mF1=-F1
 mF2=-F2
 mU1=-U1
 mU2=-U2
 mM1=-M1
 mM2=-M2
 mUR1=-UR1
 mUR2=-UR2
**
*NGEN,NSET=NCOL
 1,11,1
*ELEMENT, TYPE=B23, ELSET=COLUMN
 1,1,2
*ELGEN, ELSET=COLUMN
 1,10,1,1
**
** CONNECTOR ELEMENTS
**
** NOTE: THIS DATA LINE ORDERING TESTS GROUND/NON-GROUND INPUT MIX
**
*ELEMENT, TYPE=CONN2D2
 1002,,1
 1001,100,6
 1003,,11
*ELSET, ELSET=AXIAL
 1001,
*ELSET, ELSET=BASE
 1002,
*ELSET, ELSET=ACTUATOR 
 1003,
*ELSET, ELSET=CART-ROT
 BASE, ACTUATOR
*ELSET, ELSET=CONNECTORS
 AXIAL, BASE, ACTUATOR
** SECTION DEFINITIONS
*BEAM SECTION, SECTION=RECT, ELSET=COLUMN, MATERIAL=STEEL
 0.1,0.1
 0.0,0.0,-1.0
*CONNECTOR SECTION, ELSET=AXIAL, BEHAVIOR= CB_AXIAL
 AXIAL
*CONNECTOR SECTION, ELSET=CART-ROT, BEHAVIOR= CB_ROT
 CARTESIAN, ROTATION
**
** MATERIAL AND CONNECTOR BEHAVIOR DEFINITIONS
**
*MATERIAL, NAME=STEEL
*ELASTIC
 200.0E9,0.3
**
*CONNECTOR BEHAVIOR, NAME= CB_AXIAL
*CONNECTOR ELASTICITY, COMPONENT=1, NONLINEAR
 <mF2>,<mU2>
 <mF1>,<mU1>
 <F1>,<U1>
 <F2>,<U2>
**
*CONNECTOR BEHAVIOR, NAME= CB_ROT
*CONNECTOR ELASTICITY, COMPONENT=6, NONLINEAR
 <mM2>,<mUR2>
 <mM1>,<mUR1>
 <M1>,<UR1>
 <M2>,<UR2>
**
** BOUNDARY CONSTRAINTS (BASE STATE)
**
*CONNECTOR MOTION
 ACTUATOR,1,
 BASE,1,
 BASE,2,
*BOUNDARY
 100,1,2
**
**
*STEP
 STEP-1: OBTAIN FIRST 5 BUCKLING MODES
 Perturbation load is applied by actuation using *CONNECTOR LOAD
**
*BUCKLE
 5,
*CONNECTOR LOAD, OP=NEW
 ACTUATOR,2,-1.0
**
*OUTPUT, FIELD
*NODE OUTPUT
 U,RF
*ELEMENT OUTPUT, ELSET=COLUMN
 S,E 
*NODE PRINT
 U,
*EL PRINT, ELSET=CONNECTORS
 CTF
 CEF
 CRF
 CU
*NODE FILE
 U,RF
*EL FILE, ELSET=CONNECTORS
 CTF,CEF,CRF,CU 
*END STEP
**
*STEP
 STEP-2: OBTAIN FIRST 5 BUCKLING MODES
 Perturbation load is applied by actuation using *CONNECTOR MOTION
**
** The base state boundary conditions are defined using the 
** LOAD CASE=2 parameter.
**
** The eigenvalues obtained in this step times the force in the
** actuator (CTF2) calculated in the following static step should equal 
** the eigenvalues in Step 1
**
*BUCKLE
 5,
*CONNECTOR MOTION, LOAD CASE=1
 ACTUATOR,2,-1.0
*CONNECTOR MOTION, LOAD CASE=2, OP=NEW
 ACTUATOR,1
 BASE,1,
*BOUNDARY, LOAD CASE=2, OP=NEW
 100,1,2
*END STEP
**
*STEP, PERTURBATION
 STEP-3: STATIC STEP 
**
** The purpose of this step is to obtain the total force in the
** actuator CTF2 due to the connector motion in step 2 (LOAD CASE=1).
**
*STATIC
*CONNECTOR MOTION 
 ACTUATOR,2,-1.0
*END STEP
**
** The following steps will test the connector  behavior due to
** nonlinear elasticity.
**
*STEP, NLGEOM
 STEP-4: STATIC STEP (NLGEOM)
**
** Static step with NLGEOM to modify the base state
**
*STATIC
 0.1,1.0
*CONNECTOR LOAD, OP=NEW
 ACTUATOR,2,-1.0E5
*CLOAD
 11,6,1.0E4
**
*OUTPUT, FIELD
*NODE OUTPUT
 U,RF
*ELEMENT OUTPUT, ELSET=COLUMN
 S,E 
*OUTPUT,HISTORY,FREQ=1
*ELEMENT OUTPUT,ELSET=CONNECTORS
 CTF,CEF,CRF,CP,CU
*NODE PRINT
 U,
*EL PRINT, ELSET=CONNECTORS
 CTF
 CEF
 CRF
 CU
*NODE FILE
 U,RF
*EL FILE, ELSET=CONNECTORS
 CTF,CEF,CRF,CP,CU 
*END STEP
**
*STEP
 STEP-5: OBTAIN FIRST 5 BUCKLING MODES
 Perturbation load is applied by actuation using *CONNECTOR LOAD
*BUCKLE
 5,
*CONNECTOR LOAD
 ACTUATOR,2,-1.0
**
*OUTPUT, FIELD
*NODE OUTPUT
 U,RF
*ELEMENT OUTPUT, ELSET=COLUMN
 S,E 
*NODE PRINT
 U,
*EL PRINT, ELSET=CONNECTORS
 CTF
 CEF
 CRF
 CU
*NODE FILE
 U,RF
*EL FILE, ELSET=CONNECTORS
 CTF,CEF,CRF,CU 
*END STEP