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#1634
I'm hoping you folks can help me get going. I'm a new to Z88 Aurora and to FEM in general. Three questions at different levels:

1) I'm trying to run V2 under Windows XP SP3 on an old laptop with a single processor maxed out at 512 MB RAM. Is that already enough to cause my problems -- (2) below? (When it loads, it says it's using 389 MB. Less conveniently I could use a faster machine with dual processors and 3 GB, still under XP.)

2) I started working my way through the examples, but am not having much luck. The first example won't run the solver -- says "Faulty boundary conditions!" -- presumably because it hasn't asked me to enter any constraints. More importantly, in the second example (which leads you through entering constraints) the solver successfully starts but then quits with a Windows error message that "z88r.exe has encountered a problem and needs to close" and the error message, "Z88R : Error : Z88R! Please look at z88r.log!" (I've appended the contents of both the black progress window and z88r.log, in case they are of any help.) Any idea what I'm doing wrong?

3) General Question: I'm hoping to model in 3D a right-circular cylinder of glass (telescope mirror) whose weight is supported at several points around the middle of the edge. (I already know the support forces, which sum to the weight of course.) It's not at all clear to me how to build up this object or what kind of elements to use. Suggestions would be greatly appreciated.

Thanks! -- jclarkw





Progress Window:

*************************************************
* z88a2r Converter *
* *
> Input file z88i1.txt built successfully.
> Input file z88mat.txt built successfully.
> Input file z88i2.txt built successfully.
> Input file z88i5.txt built successfully.
> Input file z88elp.txt built successfully.
> Input file z88i5.txt built successfully.
> Input file z88int.txt built successfully.
> Input file z88man.txt built successfully.
* *
* Converter ran successfully. *
*************************************************

***** *** ***
* * * * *
* *** ***
* * * * *
***** *** ***
by Prof.Dr. FRANK RIEG (C), Germany,2012 V15.0
Z88R the linear solver for Windows, LINUX und Mac OS X
Floats: 8 Bytes
Integers: 4 Bytes
Pointers: 4 Bytes
reading solver parameter file Z88MAN.TXT
*** SICCG solver with sparse matrix storing ***
*** test mode ***
reading structure data file Z88I1.TXT
reading coordinates
reading element informations
*** start Z88AI ***
program allocated 0 MB memory

program allocated 0 MB dynamic memory
pointers assembled
vector GS needs 7503 elements
vector KOI needs 588 elements



Z88R.LOG:

opening file Z88.DYN
memory id 30 allocated
memory id 31 allocated
memory id 32 allocated
memory id 60 allocated
memory id 61 allocated
memory id 62 allocated
memory id 63 allocated
memory id 64 allocated
memory id 65 allocated
start reading function RI188I
reading Z88I1.TXT
reading coordinates
reading element information
Z88I1.TXT read, leaving reading function RI188I
start Z88AI
leaving Z88AI
vector GS needs 7503 Elemente
vector KOI needs 588 Elemente
#1635
Hello jclarkw,

welcome to world of FEA.
1)
V2 should also run on your laptop but I am not for sure. Regarding to question 3 in long term it can be less time consuming to work with the faster one. Approximately the more nodes the more computing time. But for a first test and to preprocess your work the older one should be sufficient enough.
If you notice that the computing time will hard increase than pick up your directories and solve your models with the faster one.

2)
First example: On page 12 (b1_fork_wrench.pdf) you have to set the boundary conditions. If you do not do this the solver will not run. Maybe have a look to Spider-Help this will guide you to the FEA but does not ask you to set constraints!
As far as I am concerned with Aurora V2 a massive editing in preprocessing induce failure in the z88structure.txt. Eventually it can be possible to have two points or elements overlayed. In the theoryguide.pdf on page 29 you find the correct setting of z88structure.txt and other important input files. Consistent element types and DOF for the nodes should be checked in case of emergency. Furthermore look at the sets and setsactive.txt.

3)
What elements you should use depends on several things. It is possible to use shell elements for more thin-walled cylinders but continuum elements can also guide to a right analysis. Using symmetry is one advice to you but only if it is possible.

Finally you have to model for your one but you are always welcome in our forum.

With kind regards

FRudolph
#1637
Dear FRudolph:

Do you have any suggestions about the solver crash on the second example, described in the second part of my question 2 (repeated below for convenience)? I don't know how to interpret the progress window and log file attached to my first message...

Thanks! - jclarw


"More importantly, in the second example (which leads you through entering constraints) the solver successfully starts but then quits with a Windows error message that "z88r.exe has encountered a problem and needs to close" and the error message, "Z88R : Error : Z88R! Please look at z88r.log!" (I've appended the contents of both the black progress window and z88r.log, in case they are of any help.) Any idea what I'm doing wrong?"
#1643
Sorry, but I'm getting nowhere. (I misled you about the example; it's actually the Fork Wrench that I'm trying to follow.) Every time I follow the directions (either the sketchy and confusing ones in the PDF Examples file or the more explicit ones in the video), I get a Solver error. I can't see any indication (in English at least) of what my error might be in any of the project files, LOG or otherwise. Please help!
#1646
Hello jclarkw,

to make more suggestions what to do or where the failure can be, please post or send me your project-files (michael.frisch(at)uni-bayreuth.de). That makes it much easier for us to evaluate the problem. :)

Best regards
M. Frisch
#1651
Hello again jclarkw,

i found the small mistake. The example, fork_wrench, you tired to simulate is a two dimensional problem. When you look at your boundary conditions, you fixed three coordinates: x,y and z! But you have to fix only two: the x and y coordinate, because we have a two dimensional problem. (See page 13 at the bottom in the example manual fork_wrench) :)

Best regards
Michael Frisch
#1660
>>...you fixed three coordinates: x,y and z! But you have to fix only two: the x and y coordinate, because we have a two dimensional problem.<<



Michael -- I made that change (in spite of what is shown in the video tutorial), but Solver still fails. I'm pretty sure I got to this place previously, when following the PDF tutorial instead of the video. I've sent you a new ZIP archive via private e-mail. -- jclarkw
#1661
Hello jclarkw,

that´s strange. I took your project, opened and calculate it. No error occur. Did you try this with a another example?! Occur that problem only with the fork_wrench?! I´ll send you the calculated files.

Best regards

Michael Frisch
#1667
>>that´s strange. I took your project, opened and calculate it. No error occur. Did you try this with a another example?!<<


Michael -- I have not tried any other examples. Before we go on, can you confirm that Z88 **should** run in my configuration, quoted below from my first post? Or could there be options that I haven't set correctly? -- John Willett


"I'm trying to run V2 under Windows XP SP3 on an old laptop with a single processor maxed out at 512 MB RAM. Is that already enough to cause my problems -- (2) below? (When it loads, it says it's using 389 MB. Less conveniently I could use a faster machine with dual processors and 3 GB, still under XP.)"
#1672
Hello jclarkw,

I would suggest running the same files on the faster machine and see if the solver finishes without any problem (run Michael's files so you can be sure that the project does calculate). That way we would know for sure whether we are dealing with a hardware issue or not.

Best of luck to you!

Regards

Felix Viebahn

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