*TIME POINTS with multiple regular sequences

1

A single sequence works fine:

*TIME POINTS,NAME=abc,GENERATE
0.5, 0.6, 0.02

but if I add more than one, it doesn’t use the 2nd one:

*TIME POINTS,NAME=abc,GENERATE
0.1, 0.2, 0.02
0.5, 0.6, 0.02

Sometimes it works by listing them in reverse order:

*TIME POINTS,NAME=abc,GENERATE
0.5, 0.6, 0.02
0.1, 0.2, 0.02

but that actually solves in reverse order and puts the solution in the .frd file in reverse order which is too strange. It also still misses the 2nd sequence in some cases anyway.

Any ideas how to reliably use more than one GENERATE sequence?

Here’s a complete .inp file that doesn’t work on the 2nd sequence.

*NODE
1,0,0,0
2,0.001,0,0
3,0.001,0.001,0
4,0,0.001,0
5,0,0,0.001
6,0.001,0,0.001
7,0.001,0.001,0.001
8,0,0.001,0.001
*ELEMENT,TYPE=C3D8,ELSET=EAll
1,1,2,3,4,5,6,7,8
*MATERIAL,NAME=Material
*ELASTIC,TYPE=ISOTROPIC
200000000000,0
*SOLID SECTION,ELSET=EAll,MATERIAL=Material
*BOUNDARY
1,1,3,0
2,1,3,0
3,1,3,0
4,1,3,0
*TIME POINTS,NAME=abc,GENERATE
0.1, 0.2, 0.02
0.5, 0.6, 0.02
*STEP,NLGEOM=YES
*STATIC
0.05,1,0,0
*CLOAD
5,3,-2000
6,3,-2000
7,3,-2000
8,3,-2000
*NODE FILE,TIME POINTS=abc
U
*END STEP
2

Which CalculiX release do you use ? When I run this input file, it doesn’t converge in the newest versions.

3

2.19.

I see now that it doesn’t converge at the start of the 2nd sequence (time=0.5) so perhaps that’s why it seems to be ignoring the 2nd sequence.

However, if you remove ,TIME POINTS=abc from *NODE FILE, then it solves all the way through. So I think it should equally be OK with TIME POINTS.

4

Indeed, in this case, the use of *TIME POINTS causes convergence issues.

I modified the beamnlptp.inp file from CalculiX test examples to use this definition:

*TIME POINTS,NAME=T1,GENERATE
0.4,0.6,0.2
0.7,1,0.1

It works fine for both *NODE FILE and *NODE PRINT.

5

Hmm, yea, it seems to mess up the convergence in my example, for some reason. I think it must be a bug because if you specify the same time points without GENERATE, like this, it works fine.

*TIME POINTS,NAME=abc
0.1, 0.12, 0.14, 0.16, 0.18, 0.2
0.5, 0.52, 0.54, 0.56, 0.58, 0.6

I’ll just avoid multiple GENERATE sequences.