Length issue in Mechanica 2.0

[bikerdude]

Hi Folks,


I'm using Mechanica in conjunction with Wildfire 2 and I'm hitting issues with long parts. I'm trying to run analysis on a 5.5m long pipe and I keep getting error messages when trying to run the analysis. A colleague suggested it may be a length issue within Mechanica and sure enough, when I shortened it by a metre, it ran. Is there a config setting that dictates a length to width ratio or something similar? Everything I work on is generally long and thin!

Thanks all


Leo

 

[Remmerv]

Hi Bikerdude,


It's not a MECHANICA lenght issue, it's the Pro/E default accuracy which causes the problem. By default Pro/E is on relative accuracy. This geometry will be internally translated to the geometry MECHANICA uses. This translation gets tricky or fails when the smallest edge is very small relative to the size of the model. When using MECHANICA it is advised to put the Pro/E geometryon absolute accuracy (you will need the config,pro option enable_absolute_accuracy=yes). This can be done from the setup option (FILE or EDIT menu depending on the Wildfire version), accuracy in the menu manager. Now change to an absolute accuracy value of 0.01mm (works fine in most critical cases) and you will see that you can handle a much smaller wall thickness in respect to the parts length.
If you would upgrade to a newer version of Wildfire you will see that PTC did some improvements regarding this issue and the need to change accuracy is far less than with WF2.


Good luck

 

[nschlueter]

If you are using shell elements, keep in mind that there
are recommended length to thickness ratios.

I believe its 10<l/t<1000.

I haven't run into any issues with it but you never know.