# Non-Linear Static Analysis (Hyperelasticity, Part 1)

## Non-Linear Static Analysis (Hyperelasticity, Part 1)

This analysis uses the data of tutorial/03_hyperelastic_cylinder.

### Analysis target

The analysis target is a 1/8th model of a round bar. The geometry is shown in Figure 4.3.1 and the mesh data is shown in Figure 4.3.2.

Item Description Remarks Reference
Type of analysis Non-linear static analysis (hyperelasticity) !SOLUTION,TYPE=NLSTATIC
Number of nodes 629
Number of elements 432
Element type Eight node hexahedral element !ELEMENT,TYPE=361
Material name MAT1 !MATERIAL,NAME=MAT1
Material property ELASTIC !ELASTIC
Boundary condition Restraint, Forced displacement
Matrix solver CG/SSOR !SOLVER,METHOD=CG,PRECOND=1

Fig. 4.3.1 : Shape of the round bar (1/8 model)

Fig. 4.3.2: Shape of the round bar (1/8 model)

### Analysis content

In this stress analysis, an axial tensile displacement is given to a round bar. The Mooneyâ€“Rivlin model was used in the material constitutive equation of hyperelasticity. The analysis control data are presented below.

#### Analysis control data cylinder.cnt

#  Control File for FISTR
## Analysis Control
!VERSION
3
!SOLUTION, TYPE=NLSTATIC
!WRITE,RESULT
!WRITE,VISUAL
## Solver Control
### Boundary Conditon
!BOUNDARY, GRPID=1
FIX,   3, 3, 0.0
XSYMM, 1, 1, 0.0
YSYMM, 2, 2, 0.0
### STEP
!STEP, SUBSTEPS=5, CONVERG=1.0e-5
BOUNDARY, 1
### Material
!MATERIAL, NAME=MAT1
!HYPERELASTIC, TYPE=MOONEY-RIVLIN
0.1486, 0.4849, 0.0789
### Solver Setting
!SOLVER,METHOD=CG,PRECOND=1,ITERLOG=YES,TIMELOG=YES
10000, 1
1.0e-8, 1.0, 0.0
## Post Control
!VISUAL,metod=PSR
!surface_num=1
!surface 1
!output_type=VTK
!END


### Analysis results

The results of the fifth substep are shown in Figure 4.3.3. A deformation diagram with Mises stress contours is created by REVOCAP_PrePost. A part of the analysis results log file is shown below as numerical data for the analysis results.

Fig. 4.3.3: Analysis results of deformation and Mises stress
 fstr_setup: OK
#### Result step=     0
##### Local Summary @Node    :Max/IdMax/Min/IdMin####
//U1    0.0000E+00         1  0.0000E+00         1
//U2    0.0000E+00         1  0.0000E+00         1
//U3    0.0000E+00         1  0.0000E+00         1
//E11   0.0000E+00         1  0.0000E+00         1
//E22   0.0000E+00         1  0.0000E+00         1
//E33   0.0000E+00         1  0.0000E+00         1
//E12   0.0000E+00         1  0.0000E+00         1
//E23   0.0000E+00         1  0.0000E+00         1
//E31   0.0000E+00         1  0.0000E+00         1
//S11   0.0000E+00         1  0.0000E+00         1
//S22   0.0000E+00         1  0.0000E+00         1
//S33   0.0000E+00         1  0.0000E+00         1
//S12   0.0000E+00         1  0.0000E+00         1
//S23   0.0000E+00         1  0.0000E+00         1
//S31   0.0000E+00         1  0.0000E+00         1
//SMS   0.0000E+00         1  0.0000E+00         1
##### Local Summary @Element :Max/IdMax/Min/IdMin####
//E11   0.0000E+00         1  0.0000E+00         1
//E22   0.0000E+00         1  0.0000E+00         1