Recent Posts

21

Miscellaneous Software Topics / Re: Analysis Details...

« Last post by Stephen on November 13, 2018, 01:48:25 PM »

Hi Sorin,

This is a known reporting issue which was recently fixed. I am reaching out via email to follow up.

Thanks,
Stephen

22

Miscellaneous Software Topics / Analysis Details...

« Last post by sorinb on November 13, 2018, 01:33:36 PM »

Hi,

I am trying to verify a negative margin of safety for a solid laminate composite. When I right click on the check that shows the negative margin and to the "Analysis Details..." option, the excel files does show the margin, the allowable, and a strain (I'm checking an OHC). The strain and the allowable, however, cannot reproduce the margin.
I could reproduce the margin using the running loads and a strain calculator, and using the bottom ply strain.
Is there a way to show both top and bottom plies strains in the Analysis Details spreadsheet in order to verify the margin of safety?

Thank you,
Sorin

23

Scripting / Re: Error Message

« Last post by August on October 19, 2018, 09:04:35 AM »

Hi Ruben,

This may not necessarily be a HyperSizer-specific error. The Remote Procedure Call (RPC) referenced in the error message is a Windows-level entity that manages COM interfaces in general. It appears that the RPC on your computer may be the source of the trouble here, since the COM works fine on your colleague's computer.

There seems to be a variety of fixes on Google for RPC failures. Or you might see what your IT people can do.

Is the database local, or on a server?

Best,
-August

24

Scripting / Error Message

« Last post by Ruben on October 19, 2018, 04:13:16 AM »

Hello,

When I use the spreadsheet utility, or use the COM interface through some Python code, I get a "HyperSizer has stopped working message the first time", with the attached messages from the spreadsheet and the command line. However if I immediately run it again, it works fine. It consistently doesn't work on the first attempt for me, but for my colleague it works first time. Any ideas what might be causing this issue for me? It seems to be the OpenDatabase part of the COM interface.

Regards,
Ruben

25

FEM Coupling (HyperFEA) / Re: Results from Buckling Run Deck

« Last post by Stephen on October 03, 2018, 12:30:24 PM »

Hi Jan,

For buckling cases, you are correct that we use load factors and displacements / rotations to size (using HyperFEA). If you have requested element forces for a buckling solution and the corresponding HyperSizer loadcase is active, then the forces may be used to size components.

Of course this is not desirable, so it is recommended that you deactivate (uncheck) the load case on the "Load Cases" tab of the Project Setup Form to make sure these forces do not artificially drive sizing results. This will not prevent that case from being used for HyperFEA buckling sizing.

-Stephen

26

Analyzing & Optimizing Stiffened Panels / Re: Combining Smeared Stringers with Discrete Segment Frames

« Last post by Stephen on October 03, 2018, 12:26:16 PM »

I believe what you are suggesting is the best workaround we can currently offer for this unique scenario.

Splitting the components along the frames ensures that the buckling spans are computed correctly, and then the frames can be sized independently of the stiffeners and skins. Of course in this paradigm, you do not get the benefit of the segment analysis, but iterating with FEA (especially using HyperFEA) should still result in good designs.

27

Miscellaneous Analysis & Methods / Stiffness not changed for Buckling Constraint

« Last post by JanPio on October 01, 2018, 07:51:06 AM »

Hi,
I try to implement buckling constraint of 1 into my analysis.
My settings:

• Failure analyses: only stiffness requirements
• ABD components: all D_ij (also tested with all A_ij and all D_ij, same problem)
• one buckling load case from ANSYS
• panels in the region where buckling occurs first are "one stack unstiffened" starting at 2mm thickness, Max bound is sufficiently high
• all elements are in a common display set that is selected for the constraint
• FEA loads extraction: peak element filtered (if this makes a difference for FEA constraints)

Working:

• Mode shape displayed in FEM Viewer
• correct Eigenvalue displayed in FEM Viewer
• max translation of 1 displayed in FEM Viewer
• iterations run without error
• buckling contraints, lambda_actual, lambda_req and the factor are shown in the iteration report
• the thickness is increased once from 2 to 3 mm

However, the factor does not seem to be correctly translated into required stiffnesses of the panel (see table below).
Not working:

• the thickness is not further increased
• all component factors for stiffness are =1 (see table below)
• all margins of safety are (slightly) positive (probably because the required stiffness matches the actual stiffness in the table)
• there is no Mode Detection Parameter higher than the order of E-31, which seems very low to me

      

lambda limit	lambda actual	Factor
1	0.002128684	469.7737189

D11	D11,req Current	D11,req Next	Factor
181121.4823	181121.4823	181121.4823	1

Do you know why the obviously high "Factor" does not lead to further panel thickening?
Thanks,
Jan

28

FEM Coupling (HyperFEA) / Results from Buckling Run Deck

« Last post by JanPio on September 25, 2018, 08:31:42 AM »

Hi,
I haven't found information on this in the help files: what is actually used from secondary run decks (ANSYS buckling solution) that I add for global buckling constraints? Certainly: Load Factor (for the constraint), displacements (for the mode shape), but any other loads (which I wrote to the results file)?
I assume that a run deck having ANTYPE,BUCKLE is not used to determine margins against strength failure, local buckling, cripling etc.
Thanks,
Jan

29

Analyzing & Optimizing Stiffened Panels / Combining Smeared Stringers with Discrete Segment Frames

« Last post by danvic on September 17, 2018, 01:47:38 PM »

What would be the process (or workaround) when you have frames discretely modeled with bar elements but the stringers are to be accounted for in smeared panels (spacing to be determined)?

It seems to me that the "segments" approach is intended to be used on a model that has both the stringers and frames discretely modeled using techniques 2 or 3, and not a mixture of smeared stiffeners in one direction and discrete stiffeners in the other. So far, the best alternative I could come up with is doing a conventional smeared panel sizing for the stringers and treating the frames as independent beam assemblies.

Thanks for any idea or clarification.

30

Miscellaneous Software Topics / Re: Compact Database - Assembly Project Manager

« Last post by James on September 11, 2018, 03:05:42 PM »

Compacting the assembly databases after creation is a good idea. Currently, this is not being done automatically. I've noted this down as a customer request.
In the near-term, you could write a script to compact the databases in the assembly project folder. See: http://hypersizer.com/help_7.3/#COM/Object/Application-CompactDatabase.php

Compacting a database removes all of the unused tables in the database. We recommend to compact the database if you've deleted or reimported projects. Also, if the database gets close to 2GB (Access database limit) then you should compact.

I hope this is helpful.
-James