*HEADING
 STEADY STATE  DYNAMICS PROCEDURES - /STANDARD VERIFICATION, 3D CONNECTORS
 PERTURBATION/LOAD CASE ANALYSIS
**
*NODE, NSET=NALL
 1,0.0,0.0,
 2,1.0,0.0,
 3,2.0,0.0,
 4,3.0,0.0,
*NSET, NSET=FIXED
 1,4
*PARAMETER
 C=1.0
 KAXIAL1=1.0E3
 U1=1.0E-3
 KAXIAL2=KAXIAL1/10
 U2=100*U1
 F1=KAXIAL1*U1
 F2=F1+KAXIAL2*(U2-U1)
 mF1=-F1
 mF2=-F2
 mU1=-U1
 mU2=-U2
**
** CONNECTOR ELEMENTS
**
*ELEMENT, TYPE=CONN3D2, ELSET=AXIAL
 1,1,2
 2,2,3
*ELEMENT, TYPE=CONN3D2, ELSET=ACTUATOR 
 3,3,4
*ELSET, ELSET=CONNECTORS
 AXIAL,ACTUATOR 
**
** MASS ELEMENTS
**
*ELEMENT, TYPE=MASS, ELSET=MASS
 1001,1
 1002,2
 1003,3
 1004,4
**
** SECTION DEFINITIONS
**
*MASS, ELSET=MASS
 1.0,
*CONNECTOR SECTION, ELSET=AXIAL, BEHAVIOR= CB_AXIAL
 CARTESIAN
*CONNECTOR SECTION, ELSET=ACTUATOR
 CARTESIAN
**
** CONNECTOR BEHAVIOR DEFINITIONS
**
*CONNECTOR BEHAVIOR, NAME= CB_AXIAL
*CONNECTOR ELASTICITY, COMPONENT=1, NONLINEAR
 <mF2>,<mU2>
 <mF1>,<mU1>
 <F1>,<U1>
 <F2>,<U2>
*CONNECTOR DAMPING, COMPONENT=1
 <C>,
**
** BOUNDARY CONSTRAINTS (BASE STATE)
**
*CONNECTOR MOTION
 AXIAL,2
 AXIAL,3
 ACTUATOR,2
 ACTUATOR,3
*BOUNDARY
 NALL,4,6
 FIXED,1,3
**
**
*STEP
 STEP-1: OBTAIN NATURAL MODES OF THE 2-D.O.F. SYSTEM
**
*FREQUENCY, EIGENSOLVER=SUBSPACE
 2,
**
*OUTPUT, FIELD
*NODE OUTPUT
 U
*ELEMENT OUTPUT, ELSET=CONNECTORS
 CU,CTF
*NODE PRINT
 U1,RF1
*EL PRINT, ELSET=AXIAL
 CTF1,CEF1,CRF1
 CU1,
*EL PRINT, ELSET=ACTUATOR
 CTF1,CEF1,CRF1
 CU1,
*NODE FILE
 U,
*EL FILE, ELSET=CONNECTORS
 CEF,CU
*END STEP
**
**
*STEP
 STEP-2: OBTAIN STEADY STATE DYNAMIC RESPONSE 
	 IN TERMS OF PHYSICAL DEGREES OF FREEDOM - DIRECT
** USE CONNECTOR LOAD
**
*STEADY STATE DYNAMICS, DIRECT, INTERVAL=EIGENFREQUENCY
 12, 60
**
*CONNECTOR LOAD, LOAD CASE=1
 ACTUATOR,1,-1.0
*CONNECTOR LOAD, LOAD CASE=2
 ACTUATOR,1,-1.0
**
*OUTPUT, FIELD
*NODE OUTPUT
 U
*ELEMENT OUTPUT, ELSET=CONNECTORS
 CU,CTF
*OUTPUT, HISTORY
*ELEMENT OUTPUT, ELSET=CONNECTORS
 CTF1,CEF1,CVF1,CRF1
 CU1,
*NODE PRINT, FREQUENCY=1
 U1,V1,A1,PU1
 CF1,RF1
*EL PRINT, ELSET=AXIAL, FREQUENCY=1
 CTF1,CEF1,CVF1,CRF1,
 PHCTF1,PHCEF1,PHCVF1,PHCRF1
 CU1,PHCU1
*EL PRINT, ELSET=ACTUATOR, FREQUENCY=1
 CTF1,CEF1,CVF1,CRF1
 PHCTF1,PHCEF1,PHCVF1,PHCRF1
 CU1,PHCU1
*NODE FILE
 U,
*EL FILE, ELSET=CONNECTORS
 CEF,CVF
 PHCEF,PHCVF
 CU,PHCU
*END STEP
**
**
*STEP
 STEP-3: OBTAIN STEADY STATE DYNAMIC RESPONSE 
	 IN TERMS OF PHYSICAL DEGREES OF FREEDOM - DIRECT
** USE *CONNECTOR MOTION	
**
*STEADY STATE DYNAMICS, DIRECT, INTERVAL=EIGENFREQUENCY
 12, 60
**
*CONNECTOR MOTION, LOAD CASE=1
 ACTUATOR,1,-0.1
*CONNECTOR MOTION, LOAD CASE=2
 ACTUATOR,1,-0.1
*OUTPUT, FIELD
*ELEMENT OUTPUT, ELSET=CONNECTORS
 CU,CTF
*END STEP
**
**
*STEP
 STEP-4: OBTAIN STEADY STATE DYNAMIC RESPONSE 
	 IN TERMS OF THE SYSTEM'S EIGENMODES - MODE BASED
**
*STEADY STATE DYNAMICS, INTERVAL=EIGENFREQUENCY
 12, 60
**
*CONNECTOR LOAD, LOAD CASE=1
 ACTUATOR,1,-1.0
*CONNECTOR LOAD, LOAD CASE=2
 ACTUATOR,1,-1.0
*OUTPUT, FIELD
*ELEMENT OUTPUT, ELSET=CONNECTORS
 CU,CTF
*END STEP
**
**
*STEP
 STEP-5: OBTAIN STEADY STATE DYNAMIC RESPONSE 
	 IN TERMS OF THE SYSTEM'S EIGENMODES - SUBSPACE PROJECTION
**
*STEADY STATE DYNAMICS, SUBSPACE PROJECTION, INTERVAL=EIGENFREQUENCY
 12, 60
**
*CONNECTOR LOAD, LOAD CASE=1
 ACTUATOR,1,-1.0
*CONNECTOR LOAD, LOAD CASE=2
 ACTUATOR,1,-1.0
*OUTPUT, FIELD
*ELEMENT OUTPUT, ELSET=CONNECTORS
 CU,CTF
*END STEP
**
**
*STEP, NLGEOM
 STEP-6: CHANGE THE BASE STATE
**
*STATIC
 0.1,1.0
*CLOAD
 2,1,2.0
**
*OUTPUT, FIELD
*NODE OUTPUT
 U,
*OUTPUT, FIELD
*ELEMENT OUTPUT, ELSET=CONNECTORS
 CU,CTF
*ELEMENT OUTPUT
 NFORC,ELEN
*OUTPUT, HISTORY
*ELEMENT OUTPUT, ELSET=CONNECTORS
 CTF1,CEF1,CVF1,CRF1
 CU1,CP1
*NODE PRINT, FREQUENCY=1
 U1,CF1,RF1
*EL PRINT, ELSET=AXIAL, FREQUENCY=1
 CTF1,CEF1,CVF1,CRF1,
 CU1,CP1
*EL PRINT, ELSET=ACTUATOR, FREQUENCY=1
 CTF1,CEF1,CVF1,CRF1
 CU1,CP1
*NODE FILE
 U,RF
*EL FILE, ELSET=CONNECTORS
 CEF,CVF,CP,CU
*END STEP
**
** REPEAT ALL STEPS 
**
*STEP
 STEP-7: OBTAIN NATURAL MODES OF THE 2-D.O.F. SYSTEM
**
*FREQUENCY, EIGENSOLVER=SUBSPACE
 2,
**
*OUTPUT, FIELD
*NODE OUTPUT
 U,
*OUTPUT, FIELD
*ELEMENT OUTPUT, ELSET=CONNECTORS
 CU,CTF
*NODE PRINT
 U1,RF1
*EL PRINT, ELSET=AXIAL
 CTF1,CEF1,CRF1
 CU1,
*EL PRINT, ELSET=ACTUATOR
 CTF1,CEF1,CRF1
 CU1,
*NODE FILE
 U,
*EL FILE, ELSET=CONNECTORS
 CEF,CU
*END STEP
**
**
*STEP
 STEP-8: OBTAIN STEADY STATE DYNAMIC RESPONSE 
	 IN TERMS OF PHYSICAL DEGREES OF FREEDOM - DIRECT
** USE CONNECTOR LOAD
**
*STEADY STATE DYNAMICS, DIRECT, INTERVAL=EIGENFREQUENCY
 12, 60
**
*CONNECTOR LOAD, LOAD CASE=1
 ACTUATOR,1,-1.0
*CONNECTOR LOAD, LOAD CASE=2
 ACTUATOR,1,-1.0
**
*OUTPUT, FIELD
*NODE OUTPUT
 U,
*OUTPUT, FIELD
*ELEMENT OUTPUT, ELSET=CONNECTORS
 CU,CTF
*OUTPUT, HISTORY
*ELEMENT OUTPUT, ELSET=CONNECTORS
 CTF1,CEF1,CVF1,CRF1
 CU1,
*NODE PRINT, FREQUENCY=1
 U1,V1,A1,PU1
 CF1,RF1
*EL PRINT, ELSET=AXIAL, FREQUENCY=1
 CTF1,CEF1,CVF1,CRF1,
 PHCTF1,PHCEF1,PHCVF1,PHCRF1
 CU1,PHCU1
*EL PRINT, ELSET=ACTUATOR, FREQUENCY=1
 CTF1,CEF1,CVF1,CRF1
 PHCTF1,PHCEF1,PHCVF1,PHCRF1
 CU1,PHCU1
*NODE FILE
 U,
*EL FILE, ELSET=CONNECTORS
 CEF,CVF,
 PHCEF,PHCVF,
 CU,PHCU
*END STEP
**
**
*STEP
 STEP-9: OBTAIN STEADY STATE DYNAMIC RESPONSE 
	 IN TERMS OF PHYSICAL DEGREES OF FREEDOM - DIRECT
** USE *CONNECTOR MOTION	
**
*STEADY STATE DYNAMICS, DIRECT, INTERVAL=EIGENFREQUENCY
 12, 60
**
*CONNECTOR MOTION, LOAD CASE=1
 ACTUATOR,1,-0.1
*CONNECTOR MOTION, LOAD CASE=2
 ACTUATOR,1,-0.1
*OUTPUT, FIELD
*ELEMENT OUTPUT, ELSET=CONNECTORS
 CU,CTF
*END STEP
**
**
*STEP
 STEP-10: OBTAIN STEADY STATE DYNAMIC RESPONSE 
	  IN TERMS OF THE SYSTEM'S EIGENMODES - MODE BASED
**
*STEADY STATE DYNAMICS, INTERVAL=EIGENFREQUENCY 
 12, 60
**
*CONNECTOR LOAD, LOAD CASE=1
 ACTUATOR,1,-1.0
*CONNECTOR LOAD, LOAD CASE=2
 ACTUATOR,1,-1.0
*OUTPUT, FIELD
*ELEMENT OUTPUT, ELSET=CONNECTORS
 CU,CTF
*END STEP
**
**
*STEP
 STEP-11: OBTAIN STEADY STATE DYNAMIC RESPONSE 
   	  IN TERMS OF THE SYSTEM'S EIGENMODES - SUBSPACE PROJECTION
**
*STEADY STATE DYNAMICS, SUBSPACE PROJECTION, INTERVAL=EIGENFREQUENCY
 12, 60
**
*CONNECTOR LOAD, LOAD CASE=1
 ACTUATOR,1,-1.0
*CONNECTOR LOAD, LOAD CASE=2
 ACTUATOR,1,-1.0
*OUTPUT, FIELD
*ELEMENT OUTPUT, ELSET=CONNECTORS
 CU,CTF
*END STEP

*STEP,PERTURBATION
STEP-12
PERTURBATION ANALYSIS TO TEST CASES
*STATIC
*LOAD CASE,NAME=AXIAL-1
*CLOAD
 2,1,10.0
*END LOAD CASE
*LOAD CASE,NAME=AXIAL-2
*CLOAD
 3,1,10.0
*END LOAD CASE
*OUTPUT, FIELD
*NODE OUTPUT
 U,RF
*NODE PRINT, FREQUENCY=1
 U1,V1,A1,PU1
 CF1,RF1
*EL PRINT, ELSET=AXIAL, FREQUENCY=1
 CTF1,CEF1,CVF1,CRF1,
 PHCTF1,PHCEF1,PHCVF1,PHCRF1
 CU1,PHCU1
*EL PRINT, ELSET=ACTUATOR, FREQUENCY=1
 CTF1,CEF1,CVF1,CRF1
 PHCTF1,PHCEF1,PHCVF1,PHCRF1
 CU1,PHCU1
*END STEP