*HEADING
 RESPONSE SPECTRUM ANALYSIS - /STANDARD VERIFICATION, 2D CONNECTORS
**
*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=CONN2D2, ELSET=AXIAL
 1,1,2
 2,2,3
*ELEMENT, TYPE=CONN2D2, 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
 AXIAL
*CONNECTOR SECTION, ELSET=ACTUATOR
 AXIAL
**
** 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)
**
*BOUNDARY
 NALL,2,3
 FIXED,1,
**
**
*SPECTRUM, TYPE=DISPLACEMENT, NAME=RESPD, INPUT=conn_quake_dis.inp
*SPECTRUM, TYPE=VELOCITY, NAME=RESPV, INPUT=conn_quake_vel.inp
**
**
*STEP
 STEP-1: OBTAIN NATURAL MODES OF THE 2-D.O.F. SYSTEM
*FREQUENCY, EIGENSOLVER=SUBSPACE 
 2,
**
*OUTPUT, FIELD
*NODE OUTPUT
 U,RF
*ELEMENT OUTPUT, ELSET=CONNECTORS
 CTF,CEF,CU
*NODE PRINT
 U1,RF1
*EL PRINT, ELSET=AXIAL
 CTF1,CEF1,CRF1
 CU1,
 CTF1,CEF1,CRF1
 CU1,
*NODE FILE
 U,RF
*EL FILE, ELSET=CONNECTORS
 CTF,CEF,CRF,CU
*END STEP
**
**
*STEP
 STEP-2: RESPONSE SPECTRUM ANALYSIS (RESPU)
**
*RESPONSE SPECTRUM, COMP=SRSS, SUM=SRSS
 RESPD, 1.0, 0.0, 0.0, 1.0
**
*MODAL DAMPING, MODAL=DIRECT
 1,2,0.02
*SELECT EIGENMODES
 1,2
**
*OUTPUT, FIELD
*NODE OUTPUT
 U,RF
*ELEMENT OUTPUT, ELSET=CONNECTORS
 CTF,CEF,CU
*OUTPUT, HISTORY
*ELEMENT OUTPUT, ELSET=CONNECTORS
 CTF1,CEF1,CVF1,CRF1
 CU1,
*NODE PRINT, FREQUENCY=1
 U1,V1,A1
 CF1,RF1
*EL PRINT, ELSET=AXIAL, FREQUENCY=1
 CTF1,CEF1,CVF1,CRF1,
 CU1,
*EL PRINT, ELSET=ACTUATOR, FREQUENCY=1
 CTF1,CEF1,CVF1,CRF1
 CU1,
*NODE FILE
 U,RF
*EL FILE, ELSET=CONNECTORS
 CTF,CEF,CVF,CRF
 CU,
*END STEP
**
**
*STEP
 STEP-3: RESPONSE SPECTRUM ANALYSIS (RESPV)
**
*RESPONSE SPECTRUM, COMP=SRSS, SUM=SRSS
 RESPV, 1.0, 0.0, 0.0, 1.0
**
*MODAL DAMPING, MODAL=DIRECT
 1,2,0.02
*SELECT EIGENMODES
 1,2
*END STEP