looking for fatigue example

Hi Durand,

I normally would have posted the results here on caelinux.com. Should I also post them somewhere else? Any suggestions? The only problem at the moment is a common problem: lack of time.....But as soon as I have some results, they will be posted. Merry christmas!!!

Regards,

Arnold

Dear all,

unfortunatelly, I haven't been able to really have a look at the file posted by the admnistrator at all....A shame because of the efforts, but as far as I understood right now, the calculation example provided, is based on a "standard" linear behaviour of a system. Whtat I am really looking at, is a non-proportional behaviour of a system (changing contact conditions etc). Such things, nearly no commercial fatigue program can cope with. Such a calculation also has "unit loads" but different load vectors for different load cases. This means that the analysis steps (or methodolgy) is different.

What I am currently having in mind, is the following: let's say, I have 50 load time histories of 10.000 load cases each. The behaviour of my system is non-proportional (changing contact conditions and therefore load paths etc.). After a load case analysis of all time histories, I am able to define, lets say, 20 unit load cases. Now, after calculating my unit load cases, I want to make a damage calculation. But I have my 20 load cases, the vector is different for each load case. How do I now calculate my damage? What can make it even more complicated, is that each "load history file" has a different repitition factor. To be more clear, an example. Let's say, the fatigue life to be calculated is 1 year. I have 20 files, which correspond to ahlf an hour of simulation time each. File 1 is repeated 30 times during its life, file 2 45 times, file 3 4 times, etc.

I have something (logical) in mind, but I really don't know how to programm it. Can somebody help me? I think, adding/programming/describing the lapse of operation if such a feature for code aster would not only help me, but probably a lot of engineers....

What I am trying to reach with this post, is to get a bunch of people who have the same interest and which can probably create a module/example/programming frame to handle such load cases.

Regards,

Arnold

forgot it: many thanks in advance for at least reading it and making thoughts about it. If this is of interest, results should probably be discussed with Joel and the code_aster team.

Since I don't want to post my email, simply just answer if you think you can be of help and if people answer, I will get into contact with joel to find out how we can get into contact.

Regards,

Arnold

Joel
thanks a lot for this example which helped me a lot to understand fatigue. I discoverd it just now.
Regards, Johannes

Administrator wrote:

Attachment fatig.bz2 not found

Please note that it is in "tar.bz2" format !!<br /><br />

Hello Admin,

Any idea how to alter the pre-V11 command file you have included to run in CodeAster V11+? Many of the result field names have been suddenly changed and I cannot find the documentation for the equivalent names in V11. Would you or somebody assist please? Thanks!

Regards, JMB