*HEADING
Pre-tension Section Test []
Procedures Tested: Static, Dynamic
Elements Tested: CAX4
**
*NODE
       1,          1.,          0.
       2,          2.,          0.
       3,          1.,          1.
       4,          2.,          1.
       7,          1.,          2.
       8,          2.,          2.
** pre-tension section node
*NODE,NSET=NREF
    1001,          0.,          0.
*ELEMENT, TYPE=CAX4, ELSET=ECAX
       1,       1,       2,       4,       3
       2,       3,       4,       8,       7
**local orientation matching global system 
*ORIENTATION,NAME=RECT
 1.0, 0.0, 0.0, 0.0, 1.0, 0.0
 1, 0.0
*SOLID SECTION,ELSET=ECAX,MATERIAL=MAT,ORIENT=RECT
*MATERIAL,NAME=MAT
*ELASTIC,TYPE=ENGINEERING CONSTANTS
1.E5,1.E4,1.E3,0.3,0.3,0.3,3.8E4,3.8E4,
3.8E4, 
*DENSITY
100., 
**
** Node Sets for Boundary Conditions
**
*NSET, NSET=XSYMM
       1,       3,       7
*NSET, NSET=YSYMM
       1,       2
*NSET, NSET=NPULL
       7,       8
**
** Pre-tension Sections
**
*surface,NAME=SCAX-SURFACE
1,S3
*PRE-TENSION SECTION, SURFACE=SCAX-SURFACE, NODE=1001
**
** Analysis
**
*STEP
pre-tension section by tightening
*STATIC
*BOUNDARY
XSYMM,1,,
YSYMM,2,,
NPULL,2,,
NREF,1,,0.1
*NODE FILE
U,RF
*EL FILE
S,E
*END STEP
*STEP
further loading from initial tightened state
*STATIC
*BOUNDARY
NPULL,2,,0.1
*ENDSTEP
*STEP,INC=20
release previous load while maintaining pre-tension section load
*DYNAMIC
0.005,0.1
*BOUNDARY,OP=NEW
XSYMM,1,,
YSYMM,2,,
NREF,1,,0.1
*NSET,NSET=NOUT
7,8,1001
*NODE FILE,NSET=NOUT
U,RF
*EL FILE
S, 
*ENERGY FILE
*ENDSTEP