# Non-linear Static Analysis (Hyperelasticity, Part 2)

## Non-linear Static Analysis (Hyperelasticity, Part 2)

This analysis uses the data of tutorial/04_hyperelastic_spring.

### Analysis target

The spring is the object of the analysis, the geometry is shown in Figure 4.4.1 and the mesh data is shown in Figure 4.4.2.

Item Description Notes Reference
Typo of analysis Non-linear static analysis !SOLUTION,TYPE=NLSTATIC
Number of nodes 78,771
Number of elements 46,454
Element type Ten node tetrahedral quadratic element !ELEMENT,TYPE=342
Material name MAT1 !MATERIAL,NAME=MAT1
Material property HYPERELASTIC !HYPERELASTIC,TYPE=ARRUDA-BOYCE
Boundary conditions Restraint, Concentrated force
Matrix solution CG/SSOR !SOLVER,METHOD=CG,PRECOND=1

Fig. 4.4.1: Shape of the spring

Fig. 4.4.2: Mesh data of the spring

### Analysis content

In this stress analysis, the displacement of the constrained surface shown in Fig. 4.4.1 is restrained, and the displacement is given to the forced surface. The Arrudaâ€“Boyce model was used in the material constitutive equation of hyperelasticity. The analysis control data are presented below.

#### Analysis control data spring.cnt

#  Control File for FISTR
## Analysis Control
!VERSION
3
!SOLUTION, TYPE=NLSTATIC
!WRITE,RESULT
!WRITE,VISUAL
## Solver Control
### Boundary Conditon
!BOUNDARY, GRPID=1
FIX,   1, 3, 0.0
### STEP
!STEP, SUBSTEPS=1, CONVERG=1.0e-5
BOUNDARY, 1
### Material
!MATERIAL, NAME=MAT1
!HYPERELASTIC, TYPE=ARRUDA-BOYCE
0.71, 1.7029, 0.1408
### 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 procedure

Execute the FrontISTR execution command fistr1.

$cd FrontISTR/tutorial/04_hyperelastic_spring$ fistr1 -t 4


### Analysis results

A deformation diagram with a contoured displacement is created by REVOCAP_PrePost and shown in Figure 4.4.3. A part of the log file is shown below as numerical data for the analysis results.

Fig. 4.4.3: Analysis results of deformation and displacement

#### Analysis results log 0.log

 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