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Author Topic: Laminate Allowables- Margins of Safety are quoted outside the design envelope  (Read 21648 times)

Stressed

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  • Posts: 42
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In the current version of Hypersizer the LAMINATE allowables are defined as a %age of 45 deg, 0 deg or AML. Stain allowables are determined by LINEAR interpolation between the MIN ans MAX values of say %45 deg plies in a laminate.

If a laminate is created for analysis that is outside the scope of the Hypersizer defined allowables, Hypersizer will default to the MAX or MIN definition. For example if orthotropic allowables are created between 30% and 70% 45 deg plies and the user defines a laminate with 20% 45 deg plies, the allowable property used in the analysis would be for 30% 45 deg plies.

The user should create laminates for analysis within the test envelope  (Hypersizer allowables envelope).

Margins of Safety provided by Hypersizer in the above situation would not be correct. Users with little experience of allowables or not aware of the Hypersizer analysis process would simply assume the calculated Margin of Safety is valid.

Hypersizer should provide flag, warning users that their LAMINATE analysis is outside the range of the laminate allowables and to use the Margin provided as a best approximation, or preferably modify the laminate to be within the range of the allowables envelope provided.
David Johnson
Hitech Global Solutions Inc

jjainswo

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Where to provide such a flag is the question.  It would have to be presented after the analysis.  Options:

1. Data Required in associated failure method
2. Maybe just won't consider any EL/DL outside range as an option
3. Warning message after analysis


Stressed

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  • Posts: 42
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Note: A number of customers prefer the MS not be calculated if the laminate is outside the range of the allowable properties.

The ideal would be to give the user an option of providing a preliminary Margin of Safety and a warning flag (Most likely used in preliminary design), or not provide a Laminate Margin of Safety, and  a flag to tell the user to change the laminate configuration (This option would be used for final design because in this phase the Margin of Safety must be supported by test data and allowable properties).   
 
No reply required.
David Johnson
Hitech Global Solutions Inc

jjainswo

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What about providing a such a check as an option that maybe turned on and off...say through the backdoor data file?