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
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

Shape of the spring

Fig. 4.4.1: Shape of the spring

Mesh data 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 Arruda–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
 LOADS, 2, 2, -5.0
 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
(Runs in 4 threads.)

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.

Analysis results of deformation and displacement

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

Non-linear Static Analysis (Hyperelasticity, Part 2)