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Author Topic: Problem with Effective Laminate Generation with multiple fabric materials  (Read 28167 times)

HyperSizer User

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When I create a laminate with 3 fabric types and 1 UD tape, the resulting orthotropic material the results does not show the % plies as I expect.
It seems to read all the 0 degree material as UD (when in fact some of it is 0/90 fabric orientated at 0 degree)
Is HS limited to 1 tape and 1 fabric material per laminate ??   


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    • HyperSizer Structural Sizing Software
I took a look and apparently there is a problem with Effective Laminate generation when more than one tape and/or more than one fabric are selected.  The percentages of plies in each direction are definitely wrong if that happens.   The properties of the effective laminate (engineering E, allowables, etc) will be correct, but the percentages of plies reported will be incorrect.  Unfortunately, this also means that if you have properties that are dependent on percentages of plies (e.g. allowables that are a function of %45s), these properties will not be calculated correctly.

That interface was definitely designed with only one material of each type in mind.  We will try to fix that for the next update.

Therefore with the current version of HyperSizer, if you have material properties that depend on the percentages of plies, I would recommend not using effective laminates if you have more than two materials in your laminates.  If your properties are not percentage of ply angle dependent, you should be ok using these effective laminates, just recognizing that the percentage of plies reported on the orthotropic form will be incorrect (but this will not affect the analysis results).

However, if you are using these materials as discrete laminates, there should be no problems whatsoever with any of the analysis or reporting.  In the analysis process, Hypersizer calculates percentages independently for the laminates and does not rely on a smearing process as takes place in the effective laminate generation.  I have verified that HyperSizer does calculate the percentages correctly in the analysis process if you use this laminate as a discrete laminate.

You can verify this yourself if you generate a stress report and look in the section:

Calculations for Failure Analyses
                Panel Loads and Layup Corresponding to Controlling Ply

This will list the laminate and the percentage of plies calculated in the analysis direction (0° fabrics are treated as 1/2 0° plies and 1/2 90° plies).

To delete the effective laminates that you generate, you can use the "Material Cleanup" tool on the Tools menu.