*HEADING
 CONNECTOR FRICTION BEHAVIOR IN LINEAR DYNAMICS PROCEDURES
 PERTURBATION/LOAD CASE ANALYSIS
 /STANDARD VERIFICATION, 2D CONNECTORS
**
*NODE, NSET=NALL
*NSET, NSET=FIXED
*PARAMETER
 C=1.0
 K=100.0
**
** CONNECTOR ELEMENTS
**
*ELEMENT, TYPE=CONN2D2, ELSET=FR_AXIAL
*ELEMENT, TYPE=CONN2D2, ELSET=NOFR_AXIAL
*ELSET, ELSET=AXIAL
 FR_AXIAL,NOFR_AXIAL
*ELEMENT, TYPE=CONN2D2, ELSET=ACTUATOR
*ELSET, ELSET=CONNECTORS
 AXIAL,ACTUATOR
**
** MASS ELEMENTS
**
*ELEMENT, TYPE=MASS, ELSET=MASS
**
** SECTION DEFINITIONS
**
*MASS, ELSET=MASS
 1.0,
*CONNECTOR SECTION, ELSET=FR_AXIAL, BEHAVIOR=CB_FR_AXIAL
 AXIAL
*CONNECTOR SECTION, ELSET=NOFR_AXIAL, BEHAVIOR=CB_NOFR_AXIAL
 AXIAL
*CONNECTOR SECTION, ELSET=ACTUATOR
 AXIAL
**
** CONNECTOR BEHAVIOR DEFINITIONS
**
*CONNECTOR BEHAVIOR, NAME=CB_NOFR_AXIAL
*CONNECTOR ELASTICITY, COMPONENT=1
 <K>,
*CONNECTOR DAMPING, COMPONENT=1
 <C>,
**
*CONNECTOR BEHAVIOR, NAME=CB_FR_AXIAL
*CONNECTOR ELASTICITY, COMPONENT=1
 <K>,
*CONNECTOR FRICTION, COMPONENT=1
*friction
1.0,
**
** BOUNDARY CONSTRAINTS (BASE STATE)
**
*BOUNDARY
 NALL,2,3
 FIXED,1,
**
**
*STEP
 STEP-1: OBTAIN NATURAL MODES OF THE 2-D.O.F. SYSTEM
**
*FREQUENCY, EIGENSOLVER=SUBSPACE
 2,
**
*OUTPUT, FIELD
*NODE OUTPUT
 U,RF
*NODE PRINT
 U1,RF1
*EL PRINT, ELSET=AXIAL
 CTF1,CEF1,CRF1
 CU1,
*EL PRINT, ELSET=ACTUATOR
 CTF1,CEF1,CRF1
 CU1,
*NODE FILE
 U,RF
*EL FILE, ELSET=CONNECTORS
 CTF,CEF,CRF,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,RF
*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,RF
*EL FILE, ELSET=CONNECTORS
 CTF,CEF,CVF,CRF
 PHCTF,PHCEF,PHCVF,PHCRF
 CU,PHCU
*END STEP
**
**
*STEP, NLGEOM
 STEP-3: CHANGE THE BASE STATE - ACTIVATE FRICTION
**
*STATIC
 0.05,1.0
*CLOAD
 2,1,10.0
**
*OUTPUT, FIELD
*NODE OUTPUT
 U,RF
*ELEMENT OUTPUT
 NFORC,ELEN
*OUTPUT, HISTORY
*ELEMENT OUTPUT, ELSET=CONNECTORS
 CTF1,CEF1,CVF1,CSF1,CRF1
 CU1,CP1
*NODE PRINT, FREQUENCY=1
 U1,CF1,RF1
*EL PRINT, ELSET=AXIAL, FREQUENCY=1
 CTF1,CEF1,CVF1,CSF1,CRF1,
 CU1,CP1
*EL PRINT, ELSET=ACTUATOR, FREQUENCY=1
 CTF1,CEF1,CVF1,CRF1
 CU1,CP1
*NODE FILE
 U,RF
*EL FILE, ELSET=CONNECTORS
 CTF,CEF,CVF,CSF,CRF,CP,CU,
NFORC,
*END STEP
**
** REPEAT ALL STEPS
**
*STEP
 STEP-4: OBTAIN NATURAL MODES OF THE 2-D.O.F. SYSTEM
**
*FREQUENCY, EIGENSOLVER=SUBSPACE
 2,
**
*OUTPUT, FIELD
*NODE OUTPUT
 U,RF
*NODE PRINT
 U1,RF1
*EL PRINT, ELSET=AXIAL
 CTF1,CEF1,CRF1
 CU1,
*EL PRINT, ELSET=ACTUATOR
 CTF1,CEF1,CRF1
 CU1,
*NODE FILE
 U,RF
*EL FILE, ELSET=CONNECTORS
 CTF,CEF,CRF,CU
*END STEP
**
**
*STEP
 STEP-5: 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,RF
*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,RF
*EL FILE, ELSET=CONNECTORS
 CTF,CEF,CVF,CRF
 PHCTF,PHCEF,PHCVF,PHCRF
 CU,PHCU
*END STEP
*STEP,PERTURBATION
*******************************************
***PERTURBATION ANALYSIS TO TEST LOAD 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