Non-linear Dynamic Analysis

Non-Linear Dynamic Analysis

This analysis uses the data of tutorial/13_dynamic_beam_nonlinear.

Analysis target

The target of the analysis is the same cantilevered beam as the Linear Dynamic Analysis in the previous section.

Item	Description	Notes
Type of analysis	Nonlinear dynamic analysis	!SOLUTION,TYPE=DYNAMIC !DYNAMIC,TYPE=NONLINEAR
Number of nodes	525
Number of elements	240
Element type	Ten node tetrahedral quadratic element	!ELEMENT,TYPE=342
Material name	M1	!MATERIAL,NAME=M1
Boundary conditions	Restraint,Concentrated force	!CLOAD
Matrix solution	CG/SSOR	!SOLVER,METHOD=CG,PRECOND=1

Analysis content

A nonlinear dynamic analysis is performed after the displacement of the constrained surface shown in Figure 4.12.1 is constrained and a concentrated load is applied to the load nodes. The analytical control data are shown below.

Analysis control data `beam.cnt`.

#  Control File for FISTR
## Analysis Control
!VERSION
 3
!WRITE,RESULT,FREQUENCY=100
!SOLUTION, TYPE=DYNAMIC
!DYNAMIC, TYPE=NONLINEAR
 1 , 1
 0.0, 0.1, 100000, 1.0000e-8
 0.5, 0.25
 1, 1, 0.0, 0.0
 1000, 3121, 100
 1, 1, 1, 1, 1, 1
## Solver Control
### Boundary Conditon
!BOUNDARY, GRPID=1, AMP=AMP1
 FIX, 1, 3, 0.0
!CLOAD, GRPID=1, AMP=AMP1
 CL1,    3,    -1.0
### STEP
!STEP, CONVERG=1.0e-3
 BOUNDARY, 1
 LOAD,     1
### Material
!DENSITY
 1.0e-8
!HYPERELASTIC, TYPE=NEOHOOKE
 1000.0, 0.00005
### Solver Setting
!SOLVER,METHOD=CG,PRECOND=1,ITERLOG=NO,TIMELOG=NO
 10000, 1
 1.0e-06, 1.0, 0.0
!END

Analysis procedure

Execute the FrontISTR execution command fistr1.

$ cd FrontISTR/tutorial/13_dynamic_beam_nonlinear
$ fistr1 -t 4
(Runs in 4 threads.)

Analysis results

A time series of the displacement of a monitoring node (load node, node number 3121) specified in the analysis control data is shown in Figure 4.13.1, created by Microsoft Excel. A part of the monitoring node displacement output file (dyna_disp_3121.txt) is shown below as numerical data for the analysis results.

Time-series displacement of monitoring nodes

Fig. 4.13.1: Time-series displacement of monitoring nodes

Displacement of monitoring nodes `dyna_disp_3121.txt`.

       100  1.0000E-006      3121  7.6885E-005 -7.3733E-005 -6.0988E-004
       200  2.0000E-006      3121  3.3089E-005 -7.5879E-006 -8.2481E-004
       300  3.0000E-006      3121  8.9272E-005 -5.6180E-005 -1.2550E-003
       400  4.0000E-006      3121  5.8434E-005 -2.9113E-005 -1.9326E-003
       500  5.0000E-006      3121  3.3598E-005 -3.7069E-005 -2.6955E-003
       600  6.0000E-006      3121  9.2438E-005 -2.9415E-005 -3.4297E-003
       700  7.0000E-006      3121  4.4742E-005 -1.9064E-005 -4.2128E-003
       800  8.0000E-006      3121  4.2702E-005 -3.7315E-005 -5.2563E-003
       900  9.0000E-006      3121  7.9468E-005  4.8283E-006 -6.1239E-003
      1000  1.0000E-005      3121  2.5902E-005 -3.1393E-005 -7.1463E-003
      1100  1.1000E-005      3121  6.9365E-005 -1.1486E-005 -8.3515E-003

Non-linear Dynamic Analysis