*HEADING
AIRSPRING -- 180 DEG MODEL         
******** NODAL DEFINITIONS
*NODE, NSET = FPLANE
1,2.E-2, 0.,0.
4,2.E-2, 0.,20.E-2,0.,0.,1.0
6,0.,0.,20.E-2,0.,0.,1.0
26,0.,0.,40.E-2,0.,0.,-1.0
32,6.293E-2,0.,37.771E-2,-0.58431,0.,-0.81153
38,10.698E-2,0.,36.211E-2,0.,0.,-1.0
39,11.35E-2,0.,36.211E-2,0.,0., -1.0
40,12.E-2,0.,36.211E-2,0.,0.,-1.0
41,12.E-2,0.,0.
*NGEN, LINE = C, NSET = FPLANE
6,  26, 2, , 0. , 0. , 30.E-2 , 0., 1., 0
26, 32, 1, , 0. , 0. , 30.E-2
32, 38, 1, , 10.698E-2, 0. , 43.211E-2
*NCOPY, OLD SET = FPLANE, CHANGE NUMBER = 100, 
SHIFT, MULTIPLE = 22
0., 0., 0.
0., 0., 0., 1., 0., 0., 8.18181818
*NODE, NSET = RIGID
10000, 12.E-2, 0. , 0.
*NODE, NSET = CAVITY
50000, 9.E-2 , 0. , 0.
******** RUBBER SPRING
*ELEMENT, TYPE = S4R
2,   4,  6, 106, 104
26, 26, 27, 127, 126
*ELGEN, ELSET = SPRING1
2,  11, 2, 2, 22, 100, 100
*ELGEN, ELSET = SPRING2
26, 14, 1, 1, 22, 100, 100
*ELSET,ELSET=SPRING
SPRING1,SPRING2
*SHELL SECTION, MATERIAL = RUBBER, ELSET = SPRING
6.0E-3, 
*HOURGLASS STIFFNESS
,,,100.
*REBAR LAYER
PLSREBAR,1.E-6, 3.5E-3, 0,STEEL,18,1
MNSREBAR,1.E-6, 3.5E-3, 0,STEEL,-18,1 
******** RIGID BODY (UPPER DISK)
*RIGID BODY,REFNODE=10000,ELSET=RIGELEM
*NODE,NSET=RIGNODE
11001, 12.E-2,  0.,  36.211E-2
11021,  6.5E-2, 0.,  41.711E-2
12000, 12.E-2,  0.,  41.711E-2
*NGEN,NSET=RIGNODE,LINE=C
11001, 11021, 1, 12000
*NCOPY,OLDSET=RIGNODE,CHANGE NUMBER=100,SHIFT,
MULTIPLE=22,NEWSET=NALL
0., 0., 0.
0., 0., 0., 1., 0., 0., 8.18181818
*ELEMENT,TYPE=R3D4,ELSET=RIGELEM
11001, 11001,11101,11102,11002
*ELGEN,ELSET=RIGELEM
11001, 22,100,100,  20,1,1
*ELEMENT, TYPE=R3D3, ELSET=RIGELEM
112001, 10000, 11101, 11001
112002, 10000, 11201, 11101
112003, 10000, 11301, 11201
112004, 10000, 11401, 11301
112005, 10000, 11501, 11401
112006, 10000, 11601, 11501
112007, 10000, 11701, 11601
112008, 10000, 11801, 11701
112009, 10000, 11901, 11801
112010, 10000, 12001, 11901
112011, 10000, 12101, 12001
112012, 10000, 12201, 12101
112013, 10000, 12301, 12201
112014, 10000, 12401, 12301
112015, 10000, 12501, 12401
112016, 10000, 12601, 12501
112017, 10000, 12701, 12601
112018, 10000, 12801, 12701
112019, 10000, 12901, 12801
112020, 10000, 13001, 12901
112021, 10000, 13101, 13001
112022, 10000, 13201, 13101
** CONSTRAINT TO CONNECT TOP PORTION OF
** SPRING WITH RIGID DISK
*MPC
TIE, 40, 11001
TIE, 140, 11101
TIE, 240, 11201
TIE, 340, 11301
TIE, 440, 11401
TIE, 540, 11501
TIE, 640, 11601
TIE, 740, 11701
TIE, 840, 11801
TIE, 940, 11901
TIE, 1040, 12001
TIE, 1140, 12101
TIE, 1240, 12201
TIE, 1340, 12301
TIE, 1440, 12401
TIE, 1540, 12501
TIE, 1640, 12601
TIE, 1740, 12701
TIE, 1840, 12801
TIE, 1940, 12901
TIE, 2040, 13001
TIE, 2140, 13101
TIE, 2240, 13201
******* MATERIAL DEFINITIONS
*MATERIAL, NAME = RUBBER
*HYPERELASTIC, POLYNOMIAL, N = 1
3.2E6, 0.8E6
*MATERIAL, NAME = STEEL
*ELASTIC
2.1E11, 0.3
******** CONTACT DEFINITION
*ELSET, ELSET=SPRING2A, GENERATE
26, 2126, 100
27, 2127, 100
28, 2128, 100
29, 2129, 100
30, 2130, 100
31, 2131, 100
32, 2132, 100
33, 2133, 100
34, 2134, 100
35, 2135, 100
36, 2136, 100
37, 2137, 100
38, 2138, 100
39, 2139, 100
*SURFACE, NAME = ASURF
SPRING2A,SNEG
*SURFACE,TYPE=ELEMENT, NAME = RSURF
RIGELEM,SPOS
*CONTACT PAIR, INTERACTION = SMOOTH, TYPE=SURFACE, NOTHICK
ASURF, RSURF
*SURFACE INTERACTION, NAME = SMOOTH
*SURFACE BEHAVIOR,PENALTY
,,1.e3
**
******** FLUID CAVITY
*ELEMENT, TYPE = SFM3D3, ELSET = FLUID
6001,  1,  4, 104
6040, 40, 41, 140
*ELGEN, ELSET = FLUID
6001, 22, 100, 100
6040, 22, 100, 100
*SURFACE SECTION, ELSET=FLUID
*SURFACE, TYPE=ELEMENT, NAME=CAVSURF
 SPRING, SPOS
 FLUID, SPOS
*PHYSICAL CONSTANTS, ABSOLUTE ZERO=-273.16, UNIVERSAL GAS CONSTANT=8.314
*FLUID CAVITY, NAME=SPRING, BEHAVIOR=GAS, REF NODE=50000, SURFACE=CAVSURF, AMBIENT PRESSURE=101.36E+3

*FLUID BEHAVIOR, NAME=GAS
*MOLECULAR WEIGHT
 0.044
******** NODE SETS
*NSET, NSET = N1M1, GENERATE
**101, 2201, 100
101,2101,100
*NSET, NSET = N4, GENERATE
4, 2204, 100
*NSET, NSET = N6, GENERATE
6, 2206, 100
*NSET, NSET = N40, GENERATE
40, 2240, 100
*NSET, NSET = N41, GENERATE
**41, 2241, 100
41,2141,100
*NSET,NSET=RIG
N40
*NSET, NSET = YPLN1, GENERATE
4,  26, 2
26, 40, 1
*NSET, NSET = YPLN2, GENERATE
2204, 2226, 2
2226, 2240, 1
*MPC
TIE, N1M1, 1
TIE,  N41, 10000
*BOUNDARY
1,1,3
N4,1,6
N6,2,3
YPLN1, 2
YPLN1, 4
YPLN1, 6
YPLN2, 2
YPLN2, 4
YPLN2, 6
RIGID,1,6
*****************HISTORY DEFINITION *****************
**
** STEP 1 - INFLATION STEP (5 ATMOSPHERES)
**
*STEP, NLGEOM, UNSYMM=YES
*STATIC
0.02,1.0
*MONITOR, NODE=26, DOF=3
*BOUNDARY
CAVITY,8,8, 5.066E5
*OUTPUT,FIELD,VARIABLE=PRESELECT
*NODE OUTPUT
U,RF
CF,
*CONTACT OUTPUT,VARIABLE=PRESELECT,SLAVE=ASURF
*OUTPUT,HISTORY
*NODE OUTPUT,NSET=CAVITY
PCAV,CVOL
*NODE OUTPUT, NSET=RIGID
U, RF
CF
*END STEP
**
** STEP 2 - SEAL CAVITY, RELEASE GRIP ON 
** RIGID SURFACE, AND LOAD RIGID SURFACE
**
*STEP, NLGEOM, INC=100
*STATIC
1.0,1.0
*MONITOR, NODE=10000, DOF=1
*BOUNDARY, OP=NEW
1,1,6
N4,1,6
N6,2,3
YPLN1, 2
YPLN1, 4
YPLN1, 6
YPLN2, 2
YPLN2, 4
YPLN2, 6
RIGID,2,6
*CLOAD
RIGID,1,-75.E3
*OUTPUT,FIELD,VARIABLE=PRESELECT
*NODE OUTPUT
U,RF
*OUTPUT,HISTORY
*NODE OUTPUT,NSET=CAVITY
CVOL,PCAV
*END STEP
**
** STEP 3 - PERTURBATION STEP 
** 3 LOAD CASES
**
*STEP, PERTURBATION
*STATIC
*BOUNDARY, OP=NEW
1,1,6
N4,1,6
N6,2,3
YPLN1, 2
YPLN1, 4
YPLN1, 6
YPLN2, 2
YPLN2, 4
YPLN2, 6
** LOAD CASE 1
** UNIT AXIAL DISPLACEMENT
*LOAD CASE, NAME="UNIT AXIAL DISPLACEMENT"
*BOUNDARY, OP=NEW
RIGID,1,1, 1.E-3
RIGID,2,6
*END LOAD CASE
**
** LOAD CASE 2
** UNIT LATERAL DISPLACEMENT
*LOAD CASE, NAME="UNIT LATERAL DISPLACEMENT"
*BOUNDARY, OP=NEW
RIGID,3,3, 1.E-3
RIGID,1,2
RIGID,4,6
*END LOAD CASE
**
** LOAD CASE 3
** UNIT ROTATION
*LOAD CASE, NAME="UNIT ROTATION"
*BOUNDARY, OP=NEW
RIGID,5,5, 1.E-3
RIGID,1,4
RIGID,6,6
*END LOAD CASE
*OUTPUT,FIELD,VARIABLE=PRESELECT
*NODE OUTPUT
U,RF
*END STEP
**
** STEP 4 - NONLINEAR LATERAL
** LOAD DEFLECTION CURVE
**
*STEP, NLGEOM, INC=100
*STATIC
0.1, 1.0
*CONTROLS,PARAMETERS=FIELD
,1.0
*MONITOR, NODE=10000, DOF=3
*BOUNDARY
RIGID,3,3, 2.E-2
*OUTPUT,FIELD,VARIABLE=PRESELECT
*NODE OUTPUT
U,RF
*OUTPUT,HISTORY
*NODE OUTPUT, NSET=CAVITY
CVOL,PCAV
*CONTACT OUTPUT,SLAVE=ASURF
CPRESS,
*END STEP