*HEADING

CAP PLASTICITY, UNI-AXIAL COMPRESSIVE STRESS TEST FOLLOWED BY REVERSAL OF
THE LOAD, C3D8, DISP. CONTROL
*NODE, NSET=BOT
1,0.,0.,0.
2,1.,0.,0.
3,1.,1.,0.
4,0.,1.,0.
*NODE, NSET=TOP
5,0.,0.,1.
6,1.,0.,1.
7,1.,1.,1.
8,0.,1.,1.
*NSET, NSET=ALLN
BOT, TOP
*NSET, NSET=BACK
1,4,5,8
*NSET, NSET=FRONT
2,3,6,7
*NSET, NSET=LHS
1,2,5,6                                             
*NSET, NSET=RHS
3,4,7,8
*ELEMENT, TYPE=C3D8, ELSET=EL1
1,1,2,3,4,5,6,7,8
*SOLID SECTION, ELSET=EL1, MATERIAL=CAPL
*MATERIAL,NAME=CAPL
** The material data is chosen to give G = 5000.0, BULK = 10000.0,
** first yield in pure shear        at P =   0.0,  S12 = 100.0, 
** first yield in hydro compression at P = 270.0,  S12 =   0.0,
** first yield in hydro tension     at P =-300.0,  S12 =   0.0,
** first yield (P = PA)             at P = 120.0,  S12 = 125.0
*ELASTIC
12857.1429, 0.28571429
*CAP PLASTICITY
** COHESN, BETA,    BIGR,   EVOLPI,   ALPHA,   BIGK
173.20508, 30.0, 0.61858957, 0.027, 0.69258232, 1.0
*CAP HARDENING
** PB, EVOLP
 213.0, 0.00
 222.0, 0.01
 242.0, 0.02
 282.0, 0.03
 362.0, 0.04
 522.0, 0.05
 842.0, 0.06
1482.0, 0.07
2762.0, 0.08
**
*STEP, INC=8, UNSYMM=YES
Step 1: Uni-axial compression
*STATIC, DIRECT
1., 8.0
*BOUNDARY
BACK,1
LHS, 2
BOT, 3
FRONT, 1,1, -0.08
*EL PRINT, F=999
S, 
SINV, 
E, 
PE, 
PEQC, 
*EL PRINT, POS=NODES, F=999
PEQC4, 
*NODE PRINT, F=999
U, 
RF   , 
*OUTPUT,FIELD,FREQ=999
*ELEMENT OUTPUT
S,SINV,E,PE,PEQC
*NODE OUTPUT
U,RF
*OUTPUT,FREQ=999,HISTORY
*ELEMENT OUTPUT,ELSET=EL1
S,SINV,E,PE,PEQC
*NODE OUTPUT,NSET=ALLN
U,RF
*END STEP
**
*STEP, INC=4, UNSYMM=YES
Step 2: Reverse the load to cause yielding in uni-axial tension
*STATIC, DIRECT
1., 4.0
*BOUNDARY
BACK,1
LHS, 2
BOT, 3
FRONT, 1,1, 0.0
*END STEP